WELDING     AND 
CUTTING  METALS 

BY  AID    OF 

GASES  OR  ELECTRICITY* 


BY  » 


DR.    L.    A.    GROTH 

CONSULTING    ENGINEER 

Royal  Commissioner  at  the  International  Patent  Congresses  of  Vienna,  1873, 

and   Paris,    1878  ;    Vice-  President   of  the  International  Permanent 

Commission  for  the   Protection   of  Industrial  Property,   Paris  ; 

Knight  of  the  Royal  Swedish  Order,  Gustavus  Vasa  ;  etc. 


OF  THE 

UNIVERSITY 

OF 


NEW   YORK 
D.     VAN     NOSTRAND     COMPANY 

23  MURRAY  AND  27  WARREN  STREETS 
1909 


GENERAL 


PREFACE 


AN  examination  of  the  various  methods  existing  for  the 
production  and  liquefaction  of  combustible  gases,  of  their 
easy  application  and  economical  advantages,  and  of  the 
phenomenal  advance  during  the  last  three  years  in  their 
adaptation  to  an  immense  variety  of  metallurgical  and 
engineering  operations,  which  have  hitherto  been  carried  out 
under  less  favourable  conditions,  proves  that  compressed  gases 
have  become  an  indispensable  factor  in  almost  every  branch 
of  industry. 

The  small  space  available  for  this  important  subject  will 
be  limited  to  a  description  of  welding  and  cutting  metals  by 
means  of  combustible  gases  as  well  as  the  application  of 
electric  welding. 

Eecent  investigation,  personally  made  by  the  author  in 
various  countries,  has  proved  that  welding  is  being  used  to 
a  far  greater  extent  than  is  generally  known. 

Welding  is,  however,  associated  with  and  dependent  upon 
many  different  factors,  all  of  which  must  be  simultaneously 
considered  to  enable  even  the  most  skilful  workman  to 
produce  satisfactory  results. 

A  general  description,  therefore,  of  the  various  and  distinct 
methods,  their  suitability  and  selection  for  different  operation?, 


20380:5 


iv  PEEFACE 

together  with  a  collection  of  results  and  tests  obtained,  in 
many  cases  intuitively  illustrated,  will,  it  is  hoped,  assist  in 
the  advance  in  technical  knowledge  and  lead  to  gradual 
accumulation  of  practical  experience  so  necessary  in  every 
new  industry. 

There  are,  however,  many  important  points  open  for 
investigation,  amongst  which  may  especially  be  mentioned 
the  effects  of  the  different  gases  and  their  mixtures,  as  well 
as  of  the  extreme  temperatures,  and  their  physical,  chemical, 
and  biological  action  upon  the  metals. 

It  would  also  be  of  great  importance  to  find  some  means 
whereby  an  inferior  weld,  sheltered  under  a  smooth  and 
perfect  surface,  obtained  by  the  use  of  gases  of  inferior 
purity  or  by  unskilled  labour,  could  be  detected  so  as  to 
render  that  safety  which,  in  some  branches  of  the  industry, 
is  of  vital  importance. 

By  the  introduction  of  liquefied  and  compressed  gases 
a  new  industry  of  great  importance  and  almost  unlimited 
possibilities  has  been  created.  That  which  has  already  been 
done,  although  of  great  extent,  constitutes,  however,  merely 
an  indication  of  what  really  can  be  accomplished  in  this  vast 
industrial  field  opened  up  for  investigation  and  development, 
resulting,  as  it  may,  in  the  entire  revolution  of  present 
working  methods  in  engineering  and  metallurgy. 

In  conclusion  the  author  gladly  expresses  his  indebtedness 
to  the  Editors  of  the  Technical  Press  at  home  and  abroad, 
amongst  which  may  specially  be  mentioned  the  Electrical 
Times,  Marine  Engineer  and  Naval  Architect,  and  many  others, 
as  the  Royal  Society  of  Arts  ;  Institute  of  Marine  Engineers  ; 
A.G.f.  Aluminium  Schiveissung ;  British  Oxygen  Co.,  Ld. ; 


PEEFACE  v 

Electric  Welding  Co.,  Ld. ;  Garuti  &  Pompilj ;  Hugo  Helberger, 
G.ui.b.H. ;  and  Stewarts  and  Lloyds,  Ld.,  who  have  contributed 
information  and  kindly  allowed  the  use  of  illustrations. 

The  author  also  desires  to  acknowledge  the  courteous 
manner  in  which  he  was  received  by  the  owners  and  chief 
engineers  of  many  of  the  leading  engineering  works  at  home, 
as  well  as  in  Belgium,  France,  Italy,  Austria,  and  Germany, 
and  their  readiness  to  show  and  explain  everything  that  was 
desired. 

L.   A.   GEOTH. 

LONDON,  10,  Gratton  Eoad,  West  'Kensington,  1908. 


CONTENTS 


PAGK 

PREFACE iii 

CHAPTER  I. 

General  Remarks       ...  1 

CHAPTER  II. 
GASES  AND  SOURCES  FOR  THEIR  GENERATION. 

Acetylene  .         .         ^        .         .  9 

Acetylene-Dissous 

Aggregation       .         .         .         .                           .  »         .                  .       •$ 

Atmospheric  Air        .         .         .                          .  •         •       ..«.        * 

Blau-gas    .              -^.         .         .         .  ••         •                  .19 

Brin's  Process    .         .         .         .         '•         ...  .         .         .25 

Carbide  of  Calciiim    .         . "        .         ...  .  .      -  .-        »                  7 

Electrolysis  of  Water  .       2<3 

Hydrogen           .         *         .         .         .         •  •         •         •         .21 

Liquefaction      ....                  .  .....         5 

Liquid  Air          .         .  .6 

Oxygen      .  .23 

Water  gas          .......  .33 

CHAPTER  III. 
WELDING. 

Acetylene  Welding    .....  .40 

Aluminium  Welding          .         .         .         .         .  .61 

Alumino-Thermic  Process           .                  .         .  .                  .67 

Blau-gas  Welding      .         .'        . 

Brazing     .         .         .         .•        .         1        -.       ...y  .  "                        .       82 

Chemical  Welding     .....         .     :    ,'  -  •       86 

Coal-gas  Welding      .        '•.         .         .         .  •  .         .  '      .         .87 


viii  CONTENTS 

PAP.K 

Description 35 

Different  Systems      .......  .39 

Electric  Welding .         .         .  .88 

Forging      .                  .  .     138 

Hydrogen  Welding    .         . 139 

Insulators.         .         .         .         ....         .         .  57 

Lead- burning 83 

Soldering    ........  82 

Water-gas  Welding 147 

CHAPTEE   IV. 
BLOWPIPES. 

Acetylene  Blowpipe  . ^r.  152 

,,          Illuminating  Co.,  Ld.        . 153 

Daniel's  Burner         .         .      .   •         .       ',   ••    .         .  14§ 

Draeger-Wiss  Blowpipe     .         .                           .         .         .  149 

Fouche  Blowpipe       .         '.''''•'•  •.'•?'     .      -'  .  •'-'  Ci. r       .  156 

General  Eemarks 14§ 

High- pressure  Blowpipe    .                  .         .         .         .              './  153 

Hydrogen  Blowpipe  .         .  '•  >  .         ...         .         .  149 

Jottrand  and  Lulli  Blowpipe     .         ...  149 

Low-pressure  Blowpipe     .         .         .         .         .         .         ...  154 

Oxy- Acetylene  Blowpipe  Plant         .         .         .         .         .         .'  .162 

Oxy- Hydrogen  Blowpipe  Plant         .         .         .         .         .         .  .149 

Schuckert  Blowpipe  . 149 

Societe  L'Oxhydrique  Internationale .149 

CHAPTER   V. 
WELDIXG  OF  SHEET  IRON. 

Articles  of  Complicated  Form    ......  174 

Bending  Tests .  172 

Durability  of  Welded  Seams      .         .         .     '             .         .         .  .168 

Mains  for  Gas  and  Water  .         ..       .  ,. 178 

Methods  Used    .  169 

Patent  Welded  Tubes        .         .         .         .                  .         .  .168 

Pioneer  of  Water-gas  Welding  .         .         .         .         .         .    .  .109 

Relative  Advantages  of  Cast-iron  and  Steel  Pipes     .         *        .  .182 

Corrosion  of  Wrought  Iron,  Soft  Steel,  and  Nickel  Steel  .     188 

,,       Cost  of  Cast-iron,  Steel,  and  Riveted  Pipes  .         .         .  .180 

,,        Strength  of  Cast-iron,  Steel,  and  Riveted  Pipes  .         .  .171 

'»               ',           Welded  and  Riveted  Pipes        .  171 


CONTEXTS 


Schematic  View  of  Welding  by  Coke  Fire  and  Water-gas  .170 

Seamless  Tubes 168 

Steel  Pipes .         .         .179 

Stewarts  and  Lloyds,  Limited    ........     179 

Testing  Methods        .         .         .  .         .         .  .         .172 

CHAPTER    VI. 
WELDING  APPLIED  TO  STEAM  BOILERS. 

Acetylene-Dissous  Welding        .         .         .         .         .         .         .         .197 

Advantages  of  Welded  Boiler  Joints  .         ,         .         .         .         .193 

Alumino-Thermic  Process          .         .         .         '.   '  .«;:•.       80 

Applications  of  Compressed  Gases  to  Welding 221 

Autogenous  Welding          .         .         .         .  .         .      ...     197 

British  Steam  Users'  Associations      .   / !    .         .         .         .         .         .     221 

Corrosion  .         .          .         .          *.  .         .        ...         .     198 

Cost  of  Riveted  Seams        .'..-.         .         .         .         .         .     225 

Cracks        .         .         .         ,         .         .    "     ,         .         '.        ,.         .         .     200 
Defects  of  Welds        .         .  .  .223 

Difficulties  of  Eiveted  Joints     .         .         .         .         .-  ..         .     195 

Disadvantages  of  Welded  Boiler  Joints     .         .        .*.-•'.         .        .„     194 
Electric  Welding  Process  .;.'.'";         .         .         .         .   -      .         .     212 

General  Remarks      .       ••  .•        .         »•.        .,        ,  '       <         .         .         .     192 
German  Steam  Users' Associations    .         .         .      -.         ,:        „  ,,     .     221 
Hydrogen  Welding    .         .         .         ..         .         .         .         .         ...     197 

Institute  of  Marine  Engineers :   Paper  read  by  Mr.  Harry  Ruck- 

Keene         v     .  ,         .         .         •         .         .         .         .     '•.         .     201 

Relative  Cost  of  Riveting  and  Acetylene  Welding     .        ».    •':  .*        .     22.3 
Repairs  on  Marine   Boilers:  Cracks,    Internal   Corrosion,   Outside 

Corrosion     .     »    .         .         .         .         .         .         .         .198 

,,         ,,    Steam  Boilers          .         .      "  .     ' ":.       -.         .         .'       .     195 
Tests  of  Oxy- Acetylene  Welding       .         .         .         .•        .         .         .211 

Welding  of  Tanks      ....         .         .         .  -      .-'       .         .         .     224 

Welding  versus  Riveting    .         ..         .          .          ..."       .          .     225 

CHAPTER    VII. 
CUTTING  METALS. 

Armour  Plates  .         .         .....       '  .  .  .  .  232 

Congress  of  Liege,  1901     .         .         .         .         .         .  .  .  .  229 

Consumption  of  Gas  and  cost  per  metre  of  Cut  Length  .  ..  .  234 

,,  Oxygen    .          .         ..        .         .    :     .  .  .'  .  233 

General      .         .         .         ;         .:       .-      .    i    ;  •*    >.  .  '  .  .  229 

Installation  229 


x  CONTENTS 

PAGE 

Jottrand  Blowpipe 229 

Jottrand  and  Lulli  Blowpipe      ........     230 

Metropolitan  Railway,  Paris      .         .         .         .               •    .         .  .     233 

Oxy-Hydrogen  Systems .":...     232 

Pressure  of  the  Gases .231 

Speed  of  Cutting .234 

CHAPTER  VIII. 
REPORTS  UPON  ACETYLENE  WELDING. 

Bavarian  Steam  Users'  Association  .         .         .         .         .         .  .     244 

Belgian  Steam  Users'  Association      .         .         .         . .       .      *  . '  .     248 

British  Institution  of  Marine  Engineers    .         .         .  '-"•-"' —    .:  .     201 

Chemical  Fabrik  Griesheim  Elektron         .         ,        \         .         ;  .     243 

Compagnie  des  Messageries  Maritimes      .         .    ;     .         .         .  .247 

French  Steam  Users'  Association  (Yeritas)                .      •  .         .  .     247 

German  Steam  Users'  Association     .         .         .         .         ..  .245 

Hartmann,  C.  L.  J.  .         .         .         .         .         .         .         ...     244 

Hilpert,  Dr .  .  .-  ;        ...  .  .     236 

Institute  of  Marine  Engineers  .         .                  .         *         .      '.  .     201 

International  Association  of  Steam  Users          .         .         ,*         .  .248 

Manchester  Steam  Users' Association       .         .         .         ,     .    .  .     248 

Michaelis,  Dr.  L.       ...         .         .         .       :.         .      '  .  240 

Veritas      .         .         .  •               .         .         .         .         .    •     .         *  .     247 

CHAPTER  IX. 
ACCIDENTS. 

Acetylene  Accidents  in  France           .         .         .         »         .         .  .     258 

,,         Explosive,  Limit  of  .         .         »'                 »         .      .  .  .     248 

,,         Generator,  Explosion          .         .         .         .       ...  .     255 

.,         Great  Poison     .         .         ..        .         .         ...  »     , "r . . .  .     258 

, ,        Installations,  Danger  of    .         .         .         .         .         .  .     252 

,,        Regulation  by  the  Prefect  of  Police,  Paris        ,         .  .     252 

.,        Rooms  for  Installations      .         .         .         .        '.         .  .     257 

Acetylene-Dissous,  Explosion  of  Storage  Vessel,  Fatal  Result  .     253 

Fire  at  Works    .         .         .         ...;-",  .     253 

Conseil  d; Hygiene  Publique :  Regulations        .      ?»         .         .  .     252 

Explosions  of  Acetylene  Generator  .         ,         .         i         .         .  .     255 

„  Boiler  Tubes,  Fatal  Result  .         .         .         .         .  .254 

,,  ,,  Storage  Vessel  rilled  with  Acetylene-Dissous,  Fatal 

Result  253 


CONTENTS  xi 

PACK 

Explosions  of  Acetylene-Dissous  Works 253 

Explosive  Limit  of  Acetylene    ........  252 

,,                ,,      Coal-gas        ...                                              .  252 

,,                ,,      Hydrogen .  252 

,,      Water-gas 252 

General .  251 

Prefect  of  Police,  Paris,  Eegulations         ......  252 

Rooms  for  Acetylene  Installations     .         .         .         .         .         .         .257 

Union  des  Proprietaries  d'Appareils  a  Acetylene       ....  258 


CHAPTER  X. 

LEGISLATION  RELATING  TO  CALCIC  CARBIDE 
AND  ACETYLENE. 

British  Home  Office  Committee,  1901,  dealing  with  Conditions  for 

Acetylene  Generators .         .     260 

English  Acetylene  Association  Regulations       .         .         .  .     261 

Exemption  for  certain  Admixtures  of  Acetylene  and  Oil-gas    .         .     260 
Order  of  Council,  1897,  placing  Acetylene-gas  under  the  Explosives 

Acts  .         .         .         . .         .260 

Order    of  Council,   1897,  placing  Carbide  of  Calcium  under  the 

Petroleum  Acts          .         .         .         .         .         .  *      .         .         .259 

CHAPTER  XI. 

USEFUL   ADDENDA. 

Air,  Weight  and  Volume  of     ..         .         ....        .;      ,  .         .     266 

British  Thermal  Unit         .         .         .         .         ...  .         .264 

Centigrade,  Conversion  to  Fahrenheit       .^  .         .         .         .     266 

Co-efficient  of  Heat  .         .         .         .         .         .         .  -      .         .         .265 

Combustible  Gases,  Consumption  of .         .         .         .         ....     265 

Combustion  of  Acetylene  .  .  .  .  .  .  .  .  262 

,,  Carbon .  .  .262 

,,  ,,  Coal-gas  .'....  .  ,  .  .262 

,,  Hydrogen  .  . 262 

Consumption  of  Combustible  Gases  ........     265 

English  and  Metric  Measures    .         ...        ..         .         .         •         •     -^6 

Fahrenheit,  Conversion  to  Centigrade  .  .  ,  .  .  .  266 

Metric  and  English  Measures  .  . 266 

Pressure     .         .         .         .         .         .         ...         ,         .         .     265 

Temperature  of  Fusion       .  .         .  .         ...     266 

Weight  and  Volume  of  Air  .  .  .  .  .  .  .  .  266 


LIST   OF  ILLUSTRATIONS 


FIG. 

PAGE 

1. 

27 

2. 

. 

27 

3. 

27 

4. 

29 

5. 

. 

29 

6. 

Schematic  Illustration  .     Low  Pressure  Oxy-Acetylene  Welding 

Plant     .         ....         .         

40 

i. 

Draeger's  Patent        ...         .         .  

42 

8. 

43 

9. 

4S 

10. 

TlO 

44 

11. 

44 

12. 

Trolley  Stand  for  Pair  of  Cylinders    .         . 

45 

13. 

Stretch  Testing  Apparatus  for  Cylinders   .         .         .         ,         . 

46 

14. 

Connector  between  Regulator  and  two  Cylinders 

47 

15. 

Draeger's  High-Pressure  Eefill  Pump 

48 

16. 

62 

17. 

.         .     k    •         •         ..         .         .         .         . 

64 

18. 

.         .         .         •.         .  •      .         .         .         .         .     '    . 

64 

19. 

Aluminium        ,         .         .         .         .         .         .         ... 

65 

20. 

Magnalium        .         .         .                  .         . 

66 

21. 

Wolfram  Aluminium          .         .         .  L 

66 

22. 

Complete  Rail  Welding  Outfit            ,         ... 

68 

23. 

Mould,  with  Tools     .    .     .         ....                  .         ,         .         , 

69 

24. 

Repair  before  Machining                     .         ,         .         .         . 

79 

25. 

Finished  Repair         t         .         ,         .         .         .         .         , 

79 

26. 

Cracks  in  Stern  Frame  opened  up  for  Welding          .         , 

80 

27. 

Finished  Weld  .         .         .         .         .  '               .         .1 

81 

28. 

.         ,         .                 . 

83 

29. 

Oxy-Coal  Gas  Blowpipe             .         .         .         ... 

85 

30. 

Shoulder  Taps            .         .  *     .         .                ,. 

85 

31. 

Endurance  Regulator         .         .         .         .         .         .         , 

86 

.32. 

Universal  Machine  for  Weldin<r  or  for  Electrically  Heating 

Pieces    for    Subsequent    Working,    with    Swages,    Hand- 

operated        .         .         .         .  ,       •  •  .  •  •         •         ..    .     .         , 

94 

LIST   OF  ILLUSTBATIONS 


FIG. 
1. 

•'  ;  '           .            h 

PAGE 

27 

2. 

27 

3. 

27 

4. 

.      .      .       .      . 

29 

5. 

29 

6. 

Schematic  Illustration  .     Low  Pressure  Oxy-  Acetylene  Welding 

Plant     .         .        ..         •:         .      P|        

40 

7. 

Draeger's  Patent        .         .         .  "      .  .       

42 

8. 

4S 

9. 

.           .         .."        .'        .         . 

T:O 

43 

10. 

.         .         .         .         .         .          .          .         ..... 

44 

11. 

44 

12. 

Trolley  Stand  for  Pair  of  Cylinders    ... 

45 

13. 

Stretch  Testing  Apparatus  for  Cylinders    ..... 

46 

14. 

Connector  between  Regulator  and  two  Cylinders       . 

47 

15. 

Draeger's  High-  Pressure  Ee  fill  Pump       .         .         . 

48 

16. 

•    .      ,  .  .    "   .         .         .         .         .         .         .         .         . 

62 

17. 

'•_.!.__.              •              .              .              .              .              .              .              , 

64 

18. 

64 

19. 

Aluminium         .          .          .          .         .         .         .                           "^ 

65 

20. 

Magnalium         .          .          .         .         .         .         .        '. 

66 

21. 

Wolfram  Aluminium          .         .         t         .         '.         .         ... 

66 

22. 

Complete  B.ail  Welding  Outfit           ,         ."      .  '.         .         .         . 

68 

23. 

Mould,  with  Tools     ....                                 ,         .         t 

69 

24. 

Repair  before  Machining            .         .         ,         .         .         . 

79 

25. 

Finished  Repair          f         .         , 

79 

26. 

Cracks  in  Stern  Frame  opened  up  for  Welding          .         , 

80 

27. 

Finished  Weld  .         .         .         .         .  "               .         .     '    \         . 

81 

28. 

83 

29. 

Oxy-  Coal  Gas  Blowpipe             .         .         .         .         .         . 

85 

30. 

Shoulder  Taps                     .  * 

85 

31, 

Endurance  Regulator         

86 

32. 

Universal  Machine  for  Welding  or  for  Electrically  Heating 

Pieces    for    Subsequent    Working,    with    Swages,    Hand- 

operated        .         .         .         .         .  •      .  .         .         .         .         . 

94 

xiv  .       LIST  OF  ILLUSTRATIONS 

*"!«:.  PAGE 

33.  Universal  Machine,  Normal  Pattern,  without  Swages       .         .       95 

34.  Universal  Machine,  with  Automatic  Hammer  and  Adjustable 

Anvil  for  Hand  and  Mechanical  Power          .         .         ,         .96 

35.  Hand   Chain    Welding   Machine,    for   Chains   up   to    (>   mm. 

diameter -.         .         .  97 

36.  Automatic  Chain  Welding  Machine,  for  Small  Chains       .         .  98 

37.  Automatic  Chain  Weldiug  Machine,  for  Large  Chains      .         .  99 

38.  Automatic  Chain  Welding  Machine           .         .         .         .         .  100 

39.  Ring  and  Buckle  Welding  Machine,  for  Ridgeless  Welding  in 

Swages,  Machine-driven        .         .         .         .         .         .         .101 

40.  Buckle  Welding  Machine,  with  Transformer     ....     102 

41.  Special    Machine    for    Welding    Door-hinges,    Hinge-hooks, 

Hinge-bands,  etc.,  for  Doors  and  Cupboards  ,  .  .  104 

Machine  for  End  to  End  Welding  of  Flat  Hoops,  Rings,  and  • 

similar  Articles      ......        v        ,;        .  105 

Machine  for  Simultaneously  Welding  several  Pins  or  Pieces  of 

Metal  to  Discs  or  Rings  of  Metal  (for  use  in  Watch  and 

Clock  Making)       .         .         .         .         ...         .         .  106 

44.  Point  Welding  Machine    .         .         .         .         .         .         .         .  107 

45.  Machine  for  Welding  Pulley-spokes  to  Rim  and  Hub       .         .108 

46.  Hoop  and  Rim  Welding  Machine,  specially  suited  for  Welding 

Automobile  and  Cycle  Rims          .         .         .         .         .         .     109 

47 115 

48.  .          .  .         ...      ' 115 

49.  .  ...         . 116 

50.  .          ...         ...         .         .         .         .         .         .117 

51.  .  .  .         .        .         .         .         .         .         .117 

52.  .          .         .  :  .         .         .        *         .         .         .118 

53.  . 120 

54.  Pipe  CoiL  for  Refrigerating  Machine,  Electrically  Welded  by 

Thomson  Process.  Pipes  Welded  end  to  end  by  moving 
Welding  Machine  during  Operation  of  Coiling  .  .  .122 

55.  Some  Applications  of   Electric   Welding   (Thomson   Process). 

Samples  include  Automobile  Parts,  Bicycle  Parts,  Steel 
Tubing  welded  Longitudinally,  Stampings  welded  to  Rods 
and  Tubes,  Channel  Tyres,  Baby  Carriage  Tyres,  Cutlery, 
Cylinders,  etc.  .  .  ...  .  .  "  .  .  123 

56.  Form  of  Special  Facing   for  Electrically    Welded  Flanges: 

Plain  Faced    .         .         .         ...         .         .         .         .125 

57.  Single  Spigot  and  Faucet  .         „.     .   .         .  .     126 

58.  Double  Spigot  and  Faucet          .  .         .         .         .126 

59.  Facing  Strips      ...-'.         .       ..  .         .         .126 

60.  Branch  and  Boss  on  Centre  Line  of  Pipe  .  .129 

61.  Branch  on  Centre  Line  of  Pipe      • 129 


LIST  OF  ILLUSTRATIONS  xv 


FIG. 

62. 

Branch  off  Centre  Line  of  Pipe 

PAGE 

129 

63. 

Drain  Pocket    

129 

64. 

Drain  Pocket  in  Section  .... 

129 

65. 

Tee  . 

130 

66. 

Bend    '     . 

130 

67. 

Cross 

130 

68. 

"Y"  Piece       . 

130 

69. 

Breeches  Piece         .         .         .         .                  ./..-. 

130 

70. 

Elevation          .          .          .         .                   .         .         . 

132 

71. 

End  View         .         . 

132 

72. 

Double  Bend    .         .         .         .                  ,    :     .       ;  , 

132 

73. 

Crank  Bend      .....                                   ... 

132 

74. 

''Horseshoe"  Type                                                                     ,    . 

132 

75. 

Corner  Expansion  Bend  .         .         .         .     '   .     '  .-.    •      . 

135 

76. 

"  S  "  Expansion  Bend      .         .-.''.'        .         -.         .      .   ; 

135 

77 

to  80.     Compound  and   Siding  Expansive  Joints,  Electrically 

Welded        '.         .         .                 ...         .         ^       . 

136 

81. 

Steam  Dryer,  Electrically  Welded  .        ,....-..         .         . 

137 

82. 

141 

83. 

. 

149 

84. 

Acetylene  Blowpipe,  Draeger-Wiss,  Model  1908 

150 

85. 

Fouche  Blowpipe    ..         .        .         .         .     ;   .       /. 

158 

86. 

Fouche  Cyklop  Blowpipe. 

159 

87. 

Low-pressure  Oxy-  Acetylene  Plant,  without  the  Generator  . 

162 

88. 

.        .         .'"-..         .       •  .         .         .         .         .         »•-.'.. 

169 

89. 

i    .         .         .         .         .       •...'., 

169 

90. 

169 

91. 

.                                      .                   r                 ,                  .                  ... 

170 

92. 

170 

93. 

Bending  Tests  of  Welded  Bootsdavits.     The  Imperial  Arsenal, 

Dantzig        .         .         .         .        ^         .         .        *.'                 .  172 
94.     Binding  Tests  of  Welded  Bootsdavits.     The  Imperial  Arsenal, 

Dantzig .                 .         .  173 

95 .         ....         .         .         .174 

96.  .        .         .         .        .         . 174 

97.  .        .....         .         .         .         .         .        .         .  175 

98.  .                     • .  i76 

99.  Welded  Water-mains  in  Hamburg.     F.  Fitzner,  Laurahiitte  .  177 

100.  Galloway  Boiler  with  Welded  Longitudinal  Seams,  96  q.m., 

8  Atmospheres,  2.200  m.m.  Diameter,  10,000  mm.  long. 

F.  Fitzner,  Laurahutte        .         .         .         .         .         .         .178 

101.  Repairs  by  Oxy- Acetylene  Process          .         .         .        /.         .  202 

102.  Eepairs  by  Oxy-Acetylene  Process          .         .         .         .         .  203 

103.  Repairs  by  Oxy-Acetylene  Process      .   .         .         .         .         .  204 


LIST  OF  ILLUSTRATIONS 


FIG. 


104.  Repairs  on  Main  Boilers  by  Electric  Welding 

105.  Repairs  on  Laminated  Tube  Plate  by  Electric  Welding  . 

106.  Repairs  on  Furnace   and  Combustion  Chamber  Plating  by 

Electric  Welding          .         .         .        • .         .         . 

107.  Repairs  on  Centre  Furnace  by  Electric  Wei-ling     . 

108.  Repairs  of  Cracks  in  Furnace  by  Electric  Welding 

109.  Repairs  to  a  Furnace  of  a  Boiler  by  Electric  Welding     . 

110.  Repairs  to   a   Furnace  and  Way  of   an   Adamson   Ring  by 

Electric  Welding          .         .     .'    .         .        ,.         .         .         .210 

111.  Repairs   to  Furnace  and  Combustion    Chamber  Plating  by 

Electric  Welding 211 

112.  Repairs  to  Lower  Front  Plate  by  Electric  Welding          .         .     213 

113.  Repairs  to  the  Bottom  Shell  Plate  by  Electric  Welding  .         .     214 

114.  Repairs  to  the  Combustion  Chamber  Plating  and  Tube  Plate 

of  two  Boilers  by  Electric  Welding      .         ,      rrT~     .-        .     216 

115.  Repairs  to  Wasted  Tube  Plate  of  a  Land  Boiler  by  Electric 

Welding       .         .         ....         .         ,         .         .     217 

116.  Repairs  to  the  Wasted  Seam  of  a  Land  Boiler  by  Electric 

Welding      .         .         .         ...        ".     •     .         .         .218 

117.  Repairs  by  Oxy- Acetylene  Process  .         .         .         .         .219 

118.  Test  Pieces  from  Oxy- Acetylene  Welded  Plates   :.         .         .220 

119.  Repairs  by  Oxy- Acetvlene  Process .         .         ,  222 

1 20.  Influence  of  different  Thicknesses  of  Material  upon  the  Strength 

and   Ductility  of  Autogenous  Acetylene  Welds.     Swedish 
Welding-rod  was  used  and  the  Welds  were  hammered        .     237 

121.  Influence  of  Mechanical  Treatment  of  Autogenous  Acetylene 

Welds  on  Plates  of  Various  Thicknesses       ....     238 

122.  Influence  of  Welding-rods  of  Different  Qualities  upon  the 

Strength  and  Ductility  of  Autogenous  Acetylene  Welds  on 
Plates  of  Various  Thicknesses      .         ....         .         .     239 

123 .         .         .         .         .         .         .256 

124.  256 


OF    THE 

UNIVERSITY 

OF 

.CALIF* 


WELDING 


AND 


CUTTING   METALS 


BY    AID    OF 


GASES    OR    ELECTRICITY 


CHAPTEK   I 
GENERAL  REMARKS 

THE  art  of  welding  iron  is  probably  as  old  as  the  earliest 
production  of  that  metal  by  man ;  in  fact,  the  reduction  of 
iron  in  the  primitive  forges  demanded  the  union  by  welding 
of  the  reduced  particles,  for  no  true  fusion  could  have  resulted, 
the  percentage  of  carbon  present  being  too  low. 

Previous  to  the  nineteenth  century  most  iron  work  was 
forged  by  blacksmiths  on  anvils.  It  was  the  pride  of  the 
blacksmith  to  produce  a  fine  weld,  and  the  beautiful  articles 
he  made  from  iron,  simply  at  his  fire,  even  without  a  flux- 
sometimes,  perhaps,  he  used  some  clay — are  evidence  enough 
of  what  perfection  of  skill  he  had  reached. 

Then  came  the  period  of  cast  iron,  when  everything  that 
could  be  cast  was  made  that  way,  because  it  was  cheaper. 
During  the  last  half  of  the  century  the  use  of  forged  iron  and 

w.  B 


2  WELDING  AND   CUTTING  METALS 

steel  increased  enormously,  owing  to  improved  and  cheapened 
methods  of  production. 

Where  forgings  are  so  large  that  a  smith  cannot  work  them 
satisfactorily,  because  there  is  too  much  and  too  heavy 
hammering  to  be  accomplished  in  the  short  time  the  metal 
retains  its  great  heat,  the  machine  hammer  is  resorted  to. 

The  scope  of  his  field  of  operation  being  more  and  more 
limited  by  the  progress  of  time,  which  continually  requires 
and  produces  new  methods  of  manufacture,  the  blacksmith  of 
old  gradually  disappeared  in  order  to  leave  room  for  modern 
means  of  working. 

Welding,  especially,  is  now  being  carried  out  to  great 
extent  and  advantage  by  means  of  fusion. 

During  the  last  few  years  a  new  method  of  joining  metals 
by  fusion  by  the  aid  of  compressed  combustible  gases  has 
been  introduced,  which  has  established  itself  with  an  amazing 
rapidity  in  almost  every  centre  of  industry. 

The  name  of  "  autogenous  welding,"  under  which  it  has 
been  introduced,  is,  however,  unfortunate,  indicating  as  it 
does,  that  results  would  be  produced  which  could  not  be 
obtained  by  other  means.  Autogenous  welding  was  there- 
fore and  still  is  being  introduced  with  the  specific  notice 
that  neither  flux  nor  hammering  or  pressing  is  required  in 
order  to  produce  a  perfect  weld  or  union  of  the  metals. 

Such  statements  are  not  in  accordance  with  true  facts. 
The  welding  of  cast  iron,  copper,  zinc,  and  especially  alu- 
minium and  their  alloys,  do  require  a  flux.  Forged  iron  and 
steel  are  also  to  a  great  extent  influenced  by  the  composition 
of  the  metal  to  be  added  in  order  to  complete  the  weld ;  besides 
the  form  of  the  flame,  its  temperature  and  chemical  com- 
position will  also  play  an  important  part  in  the  production  of 
a  proper  weld. 

Autogenous  welding,  even  of  the  thickness  of  2'5  to  3  m.m., 


GENERAL  REMARKS  3 

requires  the  plates  to  be  operated  upon  to  be  previously 
prepared  by  cutting  their  ends  so  as  to  form  a  groove,  into 
which  is  placed  a  piece  of  similar  metal,  in  form  of  a  bar 
or  wire,  which,  when  melted,  will  trickle  down  and  fill  the 
groove  ;  care  must  be  taken  that  the  filling  metal  of  the 
bar  is  being  perfectly  welded  to  the  metals  forming  the 
groove. 

The  thicker  the  welding  metal  is,  the  larger  must  be  the 
groove  and  the  stronger  becomes  the  weld,  which  will  have 
the  character  of  casting  in  contradiction  to  the  superior 
quality  of  the  welding  plates. 

Statements  to  the  effect  that  plates  of  from  45  to  75  m.m. 
thickness  may  be  welded  by  the  autogenous  system  with 
absolute  safety  are  simply  promises  of  fraudulent  nature. 
Such  statements  cannot  but  render  great  harm,  particularly 
to  a  new  industry,  and  may  result  in  similar  difficulties  and 
even  final  disaster,  which  the  industry  of  acetylene  lighting 
had  to  encounter. 

The  limit  of  a  qualitatively  perfect  autogenous  weld  is  to 
be  found  where  a  mechanical  finishing  of  the  weld  by 
ordinary  means  is  possible,  that  is,  probably,  within  a  thick- 
ness up  to  20  m.m. 

As  long  as  it  aims  only  at  joining  two  metals,  without  any 
special  claim  as  to  quality,  a  weld  may  be  done  at  almost  any 
thickness,  as  long  as  the  temperature  available  is  greater 
than  that  expended  in  the  weld  and  the  unavoidable  loss 
from  the  surrounding  atmosphere.  Mass-distribution  and 
large  surface  are  the  leading  points  in  this  case. 

It  is  almost  always  forgotten,  however,  that  the  principal 
and  incontestable  condition  for  producing  a  perfect  weld  is  an 
absolute  purity  of  the  combustible1  gases  employed,  and, 
furthermore,  that  the  welding  should  be  effected  without  any 
action  upon  the  metal,  chiefly  that  of  carburation. 

B2 


4  WELDING  AND  CUTTING  METALS 

Amongst  all  combustibles  the  hydrogen  alone  fulfils  these 
conditions,  and  it  offers  thereby  great  advantages  over  all 
other  combustible  gases,  particularly  over  that  of  acetylene, 
because  it  does  not  leave  any  carbon ;  used  even  in  excess, 
hydrogen  still  renders  a  reducing  flame  without  harming  the 
metal,  while  by  acetylene  and  all  other  combustible  gases  the 
metal  is  irremediably  carbonised. 

Microscopical  examination  reveals  that  out  of  five  samples 
welded  by  acetylene  four  were  oxidised  and  one  carbonised. 
This  is  easily  explained  from  the  fact  that  the  flame  of  the 
oxy-acetylene  blowpipe  is  composed  of  oxygen  and  acetylene. 
If  there  should  be  an  excess  of  acetylene,  a  carburation  takes 
place ;  if  an  excess  of  oxygen,  an  oxidation  is  produced.  In 
order  to  realise  a  neutral  flame  inventors  are  still  making 
proposals,  but  probably  without  much  prospect  of  success. 


CHAPTEK   II 

GASES    AND    SOURCES    FOR    THEIR    GENERATION 

Aggregation — Liquefaction  —Atmospheric  Air — Liquid  Air — Carbide  of 
Calcium  —  Acetylene  —  Acetylene  Dissous  —  Blau  Gas  —  Hydrogen 
— Oxygen — Water  Gas. 

AGGREGATION. 

IT  has  been  known  for  ages  that  matter  is  capable  of  existing 
in  three  different  physical  states :  the  solid  state,  the  liquid 
state,  and  the  gaseous  state. 

It  has  also  been  long  known  that  most  solids  can  be  trans- 
formed into  liquids  by  the  application  of  heat,  and  that  many 
liquids,  water  for  example,  can  be  transformed  into  vapour 
by  a  further  addition  of  heat.  Conversely,  it  is  known  that 
certain  aeriform  substances,  such  as  steam,  are  converted  into 
liquids  by  the  mere  abstraction  of  heat. 

LIQUEFACTION  OF  GASES. 

It  was  believed  that  an  essential  difference  existed  between 
gases  and  vapours,  vapours  being  condensible  to  the  fluid  form, 
while  gases  were  believed  to  be  perfectly  aeriform,  and  not 
condensible  by  any  experimental  means  at  our  disposal. 

In  the  early  part  of  the  nineteenth  century  the  validity  of 
this  distinction  came  to  be  doubted,  and  Faraday,  at  the 
suggestion  of  Davy,  undertook  the  systematic  study  of  the 
question,  with  the  result  that  he  succeeded  in  reducing  to 
liquid  form  quite  a  number  of  gases  that  had  previously 
resisted  liquefaction.  Shortly  afterwards  Thilorier,  Cagniard 


(i  WELDING  AND   CUTTING  METALS 

de  la  Tour,  Regnault,  Natterer,  and  many  others  improved  the 
methods.  Nevertheless  oxygen,  nitrogen,  and  hydrogen,  or 
the  "  permanent  gases,"  still  resisted  all  attempts,  until 
Andrews  in  1863  made  the  important  pronouncement  that  a 
certain  temperature  exists  above  which  the  gases  cannot  be 
liquefied  by  any  pressure  whatever,  this  temperature  now 
being  known  as  the  "critical  temperature,"1  and  similarly  the 
"  critical  pressure,"  or  the  tension  that  exists  in  a  liquefied 
gas  at  the  critical  temperature,  and  the  "critical  volume,"  or 
the  volume  occupied  by  a  unit  mass  of  gas  at  its  critical  point. 
The  problem  of  liquefying  the  permanent  gases,  and  any 
other  gas,  was  therefore  resolved  into  the  production  of 
exceedingly  low  temperatures. 

ATMOSPHERIC  AIR. 

This  is  a  mixture  of,  approximately, 
21  per  cent,  of  oxygen, 
78  per  cent,  of  nitrogen  by  volume,  and 

1  per  cent,  of  carbon  dioxide  and  variable  quantities 
of  water  vapour,  ammonia,  and  other  bodies,  according  to 
locality  and  conditions. 

Owing  to  the  complex  composition  of  air,  several  different 
products  are  obtained  by  its  liquefaction,  notably  liquid  oxygen 
and  nitrogen  and  solid  carbon  dioxide. 

LIQUID  AIR. 

The  principal  method  of  effecting  the  liquefaction  of 
atmospheric  air  on  a  commercial  scale,  after  Perkins,  in  1823, 
erroneously  believed  that  he  had  liquefied  air,  and  numerous 
unsatisfactory  attempts  by  others,  was  proposed  by  the  late 

1  For  Andrews'  conception  "  critical  temperature"  it  would  be  better 
to  substitute  the  conception  "  critical  density,"  or  the  least  density  which 
the  substance  can  have  as  a  liquid. —  Wrobleivski. 


GASES  AND   SOURCES  FOR   THEIR  GENERATION          7 
• 

Sir  William  Siemens  in  1857,  followed  by  the  simultaneous 
but  entirely  independent  labours  of  Louis  Cailletet  and  Edoul 
Pictet,  who  succeeded  in  liquefying  atmospheric  air  on  a  small 
laboratory  scale,  the  former  on  the  30th  December,  1877,  and 
the  latter  on  the  10th  January,  1878,  both  having  employed 
quite  different  means. 

The  impetus  and  foundation  stone  to  the  important  industry 
to  be  created  were,  however,  laid  by  Sir  James  Deicar,  who  in 
1885  succeeded  in  producing  liquid  air  from  the  atmosphere, 
an  achievement  which  aroused  great  anticipations  as  giving  the 
nucleus  to  the  solution  of  problems  of  unforeseen  importance 
to  almost  every  branch  of  industry. 

Amongst  the  numerous  and  different  methods  that  were 
suggested  from  time  to  time,  those  of  Carl  Linde  (1895) 
Conrad  Mix  and  Heylandt  (1896),  Hans  Knudsen  (1899),  and 
Eugene  Claude  (1900),  with  modifications  of  the  methods  for 
separation  of  gases  by  Rene  Lery  and  Andre  Helbrouner  (1902) 
and  Raoul  Pictet  (1903),  have  brought  the  liquefaction  of 
atmospheric  air  to  an  accomplished  fact. 

As  to  the  commercial  application  of  liquid  air,  it  may  be 
looked  upon  as  an  important,  if  not  the  principal,  source  of 
nitrogen  and  oxygen. 

CARBIDE  OF  CALCIUM. 

In  its  number  for  May,  1908,  Acetylene,  The  Lighting  Journal, 
states  that  The  Acetylene  Illuminating  Company,  Limited,  were 
the  founders  of  the  acetylene  industry  in  the  United  Kingdom, 
by  introducing  the  manufacture  of  carbide  of  calcium  in  this 
country  in  1895.  For  this  purpose  the  Wilson  patents  were 
acquired  by  the  company,  and  an  experimental  plant  was 
started  in  Leeds.  As  the  result  of  the  successful  experiments, 
a  permanent  plant  was  laid  down  at  the  Falls  of  Foyers, 
Scotland,  which  started  turning  out  carbide  on  a  commercial 


8  WELDING  AND   CUTTING  METALS 

scale  in  1896.  In  1902,  however,  it  was  found  necessary  to 
cease  carbide  manufacture,  owing  to  the  power  being  required 
for  the  manufacture  of  aluminium  and  the  company's  lease 
for  power  having  terminated. 

In  1901  the  Acetylene  Illuminating  Company,  Limited, 
acquired  the  patents  for  the  manufacture  of  dissolved 
acetylene  (acetylene-dissous)  in  Great  Britain,  the  British 
Colonies  and  Dependencies. 

Carbide  of  Calcium  is  a  dark  grey  slag  made  by  fusing 
together  coke  and  lime  in  the  intense  heat  of  an  electric 
furnace. 

The  following  formula  denotes  the  chemical  reaction  which 
produces  acetylene : 

CaC2  2H20  =      C2H2  CaOH2Q 

Calcium  carbide       Water  ~~  Acetylene          Lime 

To  put  it  simply  : 

Carbide  of  calcium  consists  of  one  atom  of  calcium  combined 
with  two  atoms  of  carbon. 

Water  consists  of  two  atoms  of  hydrogen  combined  with  one 
atom  of  oxygen. 

When  brought  into  contact, 

The  carbon  of  the  carbide  of  calcium  combines  with  the 
hydrogen  of  the  water  to  form  acetylene. 

The  calcium  of  the  carbide  of  calcium  combines  with  the 
oxygen  of  the  water  to  form  lime. 

After  acetylene  has  been  produced  the  residuum  is  a  lime 
which  may  be  used  in  the  garden  as  a  fertilizer. 

The  average  quality  of  carbide  of  calcium  will  yield  4*7  cubic 
feet  of  gas  per  pound  of  carbide. 

Carbide  of  calcium  attracts  moisture  from  the  atmosphere 
so  rapidly  that  it  must  always  be  stored  in  an  air-tight  and 
damp-proof  receptacle  to  avoid  generation  of  gas  or  crumbling 
of  the  carbide  with  consequent  deterioration  and  waste. 


GASES  AND   SOUECE3  FOB  THEIR  GENERATION          9 

Carbide  of  calcium  in  itself  is  not  an  explosive,  and  cannot 
be  made  to  explode  even  if  exposed  to  the  highest  degree  of 
heat,  but  when  water  is  added  to  it,  or  if  it  be  kept  exposed  in 
a  damp  atmosphere,  the  carbide  of  calcium  is  attacked  and 
acetylene  gas  evolved.  But  even  with  unpacked  carbide  of 
calcium,  in  a  damp  atmosphere  the  evolution  is  slow,  as  a 
hydrate  of  lime  forms  on  the  lumps  and  protects  them,  to  a 
great  extent,  from  atmospheric  influence.  If  gas  be  evolved 
and  allowed  to  accumulate,  and  a  light  be  applied,  it  will  of 
course  fire  and  explode  in  the  same  way  as  coal  gas.  Its 
escape  is  easily  detected  owing  to  its  pungent  odour. 

ACETYLENE. 

Acetylene  (C2H2)  was  first  obtained  by  Davy  in  1837  from 
the  black  mass  which  he  obtained  when  making  potassium. 
Berthelot  in  1858-59  produced  acetylene  by  passing  hydrogen 
between  the  poles  of  an  electric  arc,  and  established  the  more 
important  properties  of  the  gas  and  its  compounds.  Wohler 
in  1862  produced  calcium  carbide  by  raising  a  mixture  of 
lime,  zinc,  and  carbon  to  a  white  heat.  He  obtained  acetylene 
by  bringing  the  carbide  into  contact  with  water.  Acetylene 
was  first  liquefied  by  Cailletet  in  1877,  and  repeated  by  Ansdell 
in  1879,  whose  method  was  criticised  by  Villard,  Witlson,  and 
Suckert.  The  method  of  using  compressed  acetylene  was 
discovered  by  Claude  and  Hess. 

Acetylene  is  a  colourless  gas  of  disagreeable  odour,  which 
is  to  a  great  extent  due  to  impurities,  and  can  be  easily 
liquefied.  It  is  an  endothermic  compound  the  formation  of 
which  is  attended  by  the  absorption  or  storing  up  of  heat,  in 
contradiction  to  those  exothermic  bodies  which  evolve  heat  in 
their  formation. 

Great  care  is  evidently  required  in  its  use,  as  on  account  of 


10  WELDING  AND   CUTTING  METALS 

its  endothermic  property  its  decomposition  is  easily  effected 
when  under  pressure  and  takes  place  with  explosive  violence. 

As  acetylene  forms  an  explosive  compound  with  copper,  the 
use  of  this  metal  is  to  be  avoided. 

Another  danger  arises  from  the  use  of  impure  calcium 
carbide,  in  that  phosphuretted  hydrogen  may  be  generated 
along  with  the  acetylene. 

Unfortunately,  however,  calcium  carbide  continues  to  evolve 
acetylene  after  the  removal  of  the  water  on  account  of  the 
presence  of  aqueous  vapour,  and  the  gas  so  generated,  whilst 
the  apparatus  is  not  in  use,  accumulates  until  sufficient 
pressure  is  generated  to  force  the  water  seal. 

Dr.  Frank  Clowes  has  shown  that  the  range  of  explosibility 
of  acetylene  mixed  with  air  is  greater  than  that  of  any  other 
gas ;  escape  of  the  gas  must  therefore  be  strictly  avoided. 

The  Royal  Society  of  Arts  appointed  a  committee  to  report 
upon  the  exhibition  of  acetylene  generators  at  the  Imperial 
Institute  in  1898,  and  the  conditions  laid  down  by  the  said 
committee  form,  so  to  say,  the  foundation  stone  upon  which 
the  construction  of  acetylene  generators  is  based.  It  will 
therefore  be  of  interest  here  to  give  the  results  obtained  from 
the  tests  as  kindly  permitted  by  the  said  Society. 

The  committee  have,  for  convenience  in  classification, 
divided  the  generators  into  three  groups  :— 

1.  Those  in  which  water  is  by  various  devices  allowed  to  drip 
or  flow  in  a  thin  stream  on  to  a  mass  of  carbide,  the  evolution 
of  the  gas  being  regulated  by  the  stopping  of  the  water-feed. 

2.  Those  in  which  water  in  volume  is  allowed  to  rise  in 
contact  with  the  carbide,  the  evolution  of  the  gas  being  regu- 
lated by  the  water  being  driven  back  from  the  carbide  by  the 
increase  of  pressure  in  the  generating  chamber. 

3.  Those  in  which  the  carbide  is  dropped  or  plunged  into 
an  excess  of  water. 


GASES  AND   SOURCES  FOR  THEIR  GENERATION         11 

These  are  again  subdivided  into  : 

(a)  Automatic  generators,   or   those  which  have   a  storage 
capacity  for  gas  less  than  the  total  volume  which  the  charge 
of  carbide  is  capable  of  generating,  and  which  depend  upon 
some  special    contrivance  for  stopping  contact  between  the 
water  and  carbide. 

(b)  Non-automatic  generator*,  or  those  in  which  a  holder  of 
sufficient  capacity  is  provided  to  receive  the  whole  of  the  gas 
made  from  the  largest  charge  of  carbide  which  the  apparatus 
is  capable  of  taking. 

The  following  are  the  conditions,  laid  down  by  the  committee, 
which  the  generators  admitted  to  the  exhibition  at  the  Imperial 
Institute  were  required  to  fulfil  :— 

AUTOMATIC  GENERATORS. 

1.  Under  no  condition,  likely  to  occur  in  working,  must  it 
be  possible  for  the  pressure  in  any  part  of  the  apparatus  to 
exceed  that  necessary  to  support  a  column  of  water  100  inches 
in  height. 

2.  When  the  apparatus  is  first  charged,  in  no  case  must 
the  air  in  the  generating  chamber  and  receiver  exceed  one-fifth 
of  the  capacity  of  the  apparatus. 

3.  On  shutting  off    the  outlet  cock  of    the  generator,   the 
generation  of  the  gas  should  be  so  speedily  arrested  that  no 
large  escape  of  gas  may  need  to  take  place.     But  in  any  case 
there  must  be  an  arrangement  by  which  any  surplus  gas  can 
be  delivered  outside  the  building. 

4.  The  apparatus  should  be  so  arranged  that  the  decom- 
position  of    the   carbide    should  not   give    rise   to   excessive 
heating. 

NON-AUTOMATIC  GENERATORS. 

1.  Under  no  condition,  likely  to  occur  in  working,  must  it  be 
possible  for  the  pressure  in  any  part  of  the  apparatus  to 


12  WELDING  AND   CUTTING  METALS 

exceed  that  necessary  to  support  a  column  of  water  100  inches 
in  height. 

2.  The  air  space  in  the  generating  chamber  should  be  as 
small  as  possible,  and  the  apparatus  should  be  so  arranged 
that  the  decomposition  of  the  carbide  should  not  give  rise  to 
excessive  heating. 

3.  There  must  be  some  arrangement  by  which,  if  the  ordi- 
nary pipe  from  generator  to  holder  becomes  choked,  the  gas 
can  escape  by  blowing  a  seal  or  by  driving  back  feed- water  and 
escaping  through  the  tank. 

The  said  committee  also  expressed  the  opinion : 

That  many  types  of  acetylene  gas  apparatus  can  be  so  con- 
structed as,  with  ordinary  precaution,  to  be  absolutely  safe. 

Although  it  does  not  follow  that  the  generator  which  yields 
the  largest  amount  of  gas  is  necessarily  the  best,  yet  this 
factor  is  a  most  important  one  in  the  choice  of  any  apparatus. 
The  generators  which  combine  the  largest  yield  of  gas  with 
strength  of  material  and  simplicity  in  charging  the  carbide 
and  in  emptying  the  residue  are  those  which  will  recommend 
themselves  to  the  public. 

Where  the  public  is  most  likely  to  be  misled  is  by  the 
exaggerated  claims  made  by  makers  as  to  the  number  of  lights 
which  a  given  machine  will  supply,  and  herein  may  possibly 
be  an  element  of  danger  due  to  excessive  heating  caused  by 
too  rapid  generation.  Even  if  there  be  no  danger,  the  over- 
heating will  considerably  lessen  the  quantity  and  lower  the 
quality  of  the  acetylene  gas  evolved  from  the  carbide,  as 
well  as  tend  to  cause  smoking  of  the  burners. 

The  committee  recommend — 

That  every  apparatus  sold  should  be  accompanied  by  a 
written  guarantee  that  it  will  light  a  specified  number  of 
burners  consuming  a  given  quantity  of  gas  per  hour  over 
a  consecutive  number  of  hours  without  increasing  the 


GASES  AND   SOUKCES  FOE  THEIR  GENERATION        13 

temperature   in   any   part   of    the   carbide   receptacle    above 
228°  C.,  that  is  to  say,  the  fusing  point  of  tin. 

That  non-automatic  generators  with  a  holder  capable  of 
taking  the  gas  generated  from  the  largest  charge  of  carbide 
the  generator  will  hold  are  free  from  objections  attending  all 
automatic  generators  examined,  and  that  every  generator 
should  be  fitted  with  an  arrangement  by  which  all  air  can  be 
rinsed  out  of  the  generating  chamber  by  acetylene  or  some 
inert  gas  before  action  is  allowed  to  commence  between  the 
water  and  carbide. 

That  every  generator  should  be  fitted  with  a  purifying 
chamber  or  chambers  in  which  the  acetylene  is  purified  from 
ammonia  and  sulphuretted  and  phosphuretted  hydrogen,  and 
from  other  impurities. 

Another  important  point  is  the  length  of  time  over  which 
generation  of  gas  continues  after  the  addition  of  water  to  the 
carbide  has  ceased. 

The  general  idea  which  seems  to  exist  among  makers  of 
automatic  apparatus  of  this  type  is  that  all  they  have  to  do  in 
order  to  stop  the  generation  of  acetylene  is  to  stop  the  water 
supply ;  this,  however,  is  an  utter  fallacy,  as  liberation  of  gas 
continues  with  ever-increasing  slowness  for  sometimes  an 
hour  and  three-quarters  after  the  water  supply  has  ceased, 
whilst  the  gas  so  evolved  is  very  considerable  in  volume. 
The  length  of  time  over  which  the  generation  extends  will  of 
course  depend  to  a  certain  extent  upon  the  amount  of  water 
added,  the  percentage  of  carbide  undecomposed,  and  the 
temperature  at  which  the  mass  of  carbide  happens  to  be  when 
the  water  supply  ceases,  whilst  the  generation  will  itself 
depend  upon 

The  dehydration  of  the  calcic  hydrate  first  formed,  and 

The  decomposition  of  water  condensed  from  the  gas  present 
as  the  temperature  of  the  generator  falls. 


14  WELDING  AND   CUTTING  METALS 

TABULATING  THE  RESULTS. 

These  results  are  of  very  great  interest,  as  they  not  only 
show  clearly  the  facts  already  pointed  out,  but  indicate  that 
in  any  automatic  apparatus  on  this  principle  the  cut-off  should 
be  so  arranged  that  at  least  one-fourth  of  the  total  holder 
capacity  is  still  available  to  store  the  slowly  generated  gas. 

Another  very  important  deduction  to  be  derived  from  the 
figures  is  the  large  excess  of  water  over  and  above  the 
theoretical  quantity  required  to  ensure  complete  decomposi- 
tion of  the  carbide  by  this  process,  this  being  to  a  certain 
extent  dependent  upon  the  form  of  the  gensrator. 

According  to  theory,  64  parts  by  weight  of  carbide  require 
only  36  parts  by  weight  of  water  to  completely  decompose 
them  and  convert  the  lime  into  calcic  hydrate.  This  would 
mean  that  each  pound  of  calcic  carbide  needs  a  little  under 
half  a  pint  of  water  to  complete  the  decomposition,  whilst 
owing  to  evaporation  due  to  the  heat  produced,  half  the  added 
water  is  driven  off  as  steam  with  the  acetylene  or  left 
mechanically  adhering  to  the  lime,  and  the  smallest  quantity 
likely  to  complete  the  action  would  be  a  pint  to  a  pound  of 
carbide  ;  in  reality  the  only  way  is  to  add  sufficient  water 
to  drown  the  residue. 

If  this  is  not  done  the  lime  forms  so  protective  a  coating  to 
the  carbide  that  small  quantities  often  remain  undecomposed, 
and  if  the  residues  are  thrown  into  a  drain  or  cesspool,  the 
evolution  of  acetylene  would  give  an  explosive  mixture, 
which,  on  account  of  its  low  point  of  ignition,  would  be  a 
serious  danger. 

Points  of  considerable  interest  to  the  generator  maker  are 
the  space  occupied  by  a  given  weight  of  carbide,  the  volume 
of  the  lime  formed  from  it  on  decomposition,  and  the  volume 
of  gas  that  can  be  evolved  from  a  given  space  filled  with  carbide. 


GASES  AND  SOUECES  FOR  THEIR  GENERATION        15 

The  density  of  calcic  carbide  is  2*2,  and  therefore  a  cubic 
foot  of  solid  carbide  would  weigh  137  Ibs.  In  practice,  how- 
ever, the  weight  of  carbide  which  can  be  got  into  a  cubic  foot 
space  depends  upon  the  size  commercially  sent  out.  A  fair 
average  would  be  80  Ibs.  per  cubic  foot  of  carbide  space,  and 
this  weight  of  carbide  at  5  cubic  feet  per  Ib.  would  yield  400 
cubic  feet  of  acetylene. 

One  pound  of  pure  calcic  carbide  yields  1'15  Ibs.  of  slaked 
lime  (one  kg.  of  carbide  yields  1*156  gr.  of  slaked  lime), 
and  the  volume  this  will  occupy  depends  entirely  upon  the 
way  in  which  the  water  is  brought  in  contact  with  it. 

In  an  automatic  apparatus  of  the  first  class,  where  water 
drips  slowly  upon  the  carbide  in  sufficient  quantity  to  decompose 
it  but  not  to  flood  it,  the  lime  swells  up  and  occupies  2  to  2*5 
times  the  bulk  of  the  original  carbide ;  when,  however,  the 
water  flows  in  more  rapidly,  the  impact  of  the  water  beats 
down  the  lime  and  the  space  occupied  is  not  so  large. 

In  generators  of  the  second  class,  in  which  water  rises  from 
below,  the  weight  of  the  undecomposed  carbide  above  it 
presses  down  the  lime  below  and  keeps  it  in  a  compact  mass 
occupying  about  half  more  space  than  the  carbide  from  which 
it  was  formed. 

With  the  third  type  of  generator  it  really  becomes  a  question 
of  the  rate  at  which  the  excess  of  undissolved  calcic  hydrate 
settles,  and  this  will  be  discussed  later  on. 

The  large  proportion  of  water  vaporised  during  the  evolu- 
tion of  acetylene  at  once  draws  attention  to  the  necessity  of 
arranging  all  the  generator  connections  in  such  a  way  that 
condensation  shall  not  lead  to  stoppage  of  the  delivery  pipes. 

It  must  also  be  clearly  borne  in  mind  tbat  the  liquid 
products  condensible  from  the  gas  are  of  the  most  corrosive 
character  both  to  paint  and  metal. 

The  moment  that  acetylene  is  subjected  to  the  action  of 


16  WELDING  AND  CUTTING  METALS 

high  temperatures,  changes  of  great  complexity  at  once  com- 
mence, causing  a  great  deal  of  impurities,  and  the  tar  is 
likely  to  cause  considerable  trouble,  as  it  is  of  very  viscous 
character,  and,  if  it  condenses  in  the  delivery  tubes,  causes  the 
lime-dust  and  carbon  particles  to  collect  and  bring  about 
stoppage. 

A  still  more  important  evil,  however,  is  to  be  found  in  the 
alteration  which  takes  place  in  the  composition  of  the  gas, 
and  which  reduces  the  illuminating  value  of  the  gas  to  a 
serious  extent. 

A  very  considerable  proportion  of  the  generation  takes 
place  at  a  temperature  above  600°  C.,  about  which  point 
polymerisation  commences.  As  benzene  forms  a  large  pro- 
portion of  it,  it  is  carried  forward  as  vapours  and  remains 
suspended  even  in  its  passage  through  the  gas-holder  and 
ordinary  pipes.  Benzene  requires  three  times  the  volume  of 
air  for  combustion  that  acetylene  does,  and  the  result  is  that 
the  most  perfect  acetylene  burner  shows  a  tendency  to  smoke 
directly  any  quantity  of  benzene  is  formed. 

When  acetylene  has  been  made  in  a  generator  at  an  undue 
temperature,  it  carries  with  it  benzene  vapour,  which  as  it 
commences  to  condense  assumes  a  vesicular  form,  and  on 
coming  to  the  extremely  minute  holes  which  form  the 
apertures  of  the  burner  the  mechanical  scrubbing  which  it 
encounters  causes  the  breaking  up  of  the  vesicles  and  the 
deposition  of  the  benzene  and  other  hydrocarbons  held  in 
suspension  by  benzene,  which  soak  into  the  steatite  and 
carbonise.  The  pressure  of  finely- divided  carbon  has  a  great 
effect  in  determining  the  decomposition  of  acetylene  itself,  so 
that  a  rapid  growth  of  carbon  takes  place  at  the  burner,  and 
no  ordinary  clearing  of  the  deposited  carbon  from  the  exterior 
will  ever  make  the  nipple  fit  for  constant  use  again. 

It  will  be  found   with  experience  that   the  smoking  of  a 


GASES  AND  SOURCES  FOR  THEIR  GENERATION        17 

burner  will  be  overcome  quite  as  much  by  attention  to  the 
temperature  in  the  generator  as  to  the  burner  itself,  and  where 
a  generator  is  in  use  which  gives  overheating,  a  well-arranged 
scrubbing  apparatus  that  would  get  rid  of  the  benzene  from 
the  gas  would  be  found  a  distinct  advantage  in  stopping 
burner  troubles. 

At  first  sight  these  results  seem  an  absolute  condemnation 
of  the  second  type  of  generators,  but  the  fact  remains  that  they 
constitute  a  very  large  percentage  of  those  on  the  market, 
and  that  the  best  of  them  show  no  signs  of  overheating. 

The  reason  of  this  apparent  anomaly  is  that  under  certain 
conditions,  which  can  be  clearly  defined,  excessive  heating  is 
avoided. 

The  raising  bell  which  draws  a  mass  of  wet  carbide  above 
the  surface  of  the  water  is  bad  from  every  point  of  view. 

But  generators  in  which  water  rises  from  below  and  so 
attacks  the  carbide  can  be  made  safe  if  the  arrangements  are 
such  that  the  water  is  never  driven  back  from  the  carbide  and 
the  bulk  of  carbide  is  sufficiently  subdivided.  Under  these 
conditions  the  slowly  rising  water  is  always  in  excess  at  the 
point  where  it  decomposes  the  carbide,  so  that  the  evaporation 
by  rendering  heat  latent  keeps  down  the  temperature,  and 
although  the  steam  so  formed  partly  decomposes  the  carbide 
in  the  upper  portion  of  the  charge,  the  action  is  never 
sufficiently  rapid  to  give  anything  approaching  a  red  heat. 
In  order  to  fulfil  these  conditions  it  is  necessary  that  there 
should  be  a  holder  of  considerable  capacity,  and  that  the 
leading  tube  conducting  the  gas  from  the  generator  to  the 
holder  should  be  of  sufficient  diameter  to  freely  conduct  away 
the  gas,  the  water  at  the  same  time  being  allowed  to  rise  in  the 
generator  so  slowly  as  to  do  away  with  any  risk  of  over- 
generation. 

In  the  best  generators  of  this  class  these  conditions  are  more 

w.  c 


18  WELDING  AND   CUTTING  METALS 

or  less  approached,  and  it  is  unusual  to  find  that  the  melting 
point  of  tin,  228°  C.,has  been  reached  in  the  charge  of  carbide 
during  decomposition. 

Where  generators  of  this  class  are  automatic  and  have  no 
rising  holder  to  take  the  gas,  it  is  found  that  they  work  satis- 
factorily when  supplying  the  number  of  lights  for  which  they 
were  designed,  but  if  they  are  over-driven  and  the  action 
becomes  too  violent,  excessive  heating  takes  place,  whilst  the 
turning  off  of  the  gas,  and  consequent  driving  back  of  the 
water  from  the  carbide,  also  has  a  tendency  to  cause  it.  If 
however,  the  water  has  risen  sufficiently  slowly,  the  carbide 
below  the  surface  has  been  practically  all  decomposed,  so  that 
the  heating  only  takes  place  over  a  limited  zone. 

The  makers  of  generators  that  are  liable  to  give  rise  to 
excessive  heating  invariably  deny  the  possibility  of  such  an 
action  taking  place  with  their  generator,  and,  if  it  is  proved, 
fall  back  upon  the  defence  that,  even  if  the  mass  does  become 
red  hot,  there  is  no  particular  danger. 

In  such  generators  the  active  danger  of  explosion  only 
exists  whilst  any  air  is  left  mixed  with  the  acetylene,  and  in 
those  which  have  holders  to  take  the  gas  as  it  is  formed, 
the  air  remaining  in  the  generator  is  swept  rapidly  over 
into  the  holder  and  out  of  the  range  of  the  ^ource  of  heat ; 
but  with  automatic  generators  this  is  not  always  the  case,  and 
the  air  space  in  the  generators  should  always  be  made  as  small 
as  possible,  and  some  arrangement  should  be  adopted,  if 
possible,  by  which  the  air  in  the  generator  could  be  rinsed  out 
by  a  little  of  the  previously  produced  acetylene  before  decom- 
position of  the  carbide  by  water  commences. 

Under  these  circumstances  danger  from  explosion  during 
generation  would  disappear,  but  the  drawbacks  of  smoky  flames, 
reduced  illuminating  power ,  and  choking  tubes  would  still  remain. 

The  generators  of  the  third  class  are  those  in  which  carbide 


GASES  AND  SOUKCES  FOR  THEIR  GENERATION        19 

is  allowed  to  fall  into  an  excess  of  water,  and  these  have  many 
advantages.  In  such  generators,  as  long  as  there  is  water 
present,  and  lime  sludge  is  not  allowed  to  accumulate,  it  is 
impossible  to  get  above  a  temperature  of  100°  C.,  whilst  with 
a  properly  arranged  tank  the  temperature  never  exceeds  the 
air  temperature  by  more  than  a  few  degrees.  Under  these 
conditions  the  absence  of  polymerisation  and  the  washing  of 
the  nascent  and  finely-divided  bubbles  of  gas  by  the  lime  water 
in  the  generator  yields  acetylene  of  a  degree  of  purity 
unapproached  by  any  other  form  of  apparatus. 

This  form  of  generator,  however,  although  exhibiting  the 
great  advantages  mentioned  above,  has  the  drawback  of  being 
one  of  the  least  economical  in  the  output  of  acetylene  per 
pound  of  carbide  used,  as  the  gas  having  to  bubble  through 
the  water  is  rapidly  dissolved  by  it,  whilst  in  an  apparatus  in 
which  only  the  surface  of  the  water  touches  the  gas  the 
amount  dissolved  is  comparatively  small.  The  result  is  that 
with  generators  of  this  class  the  generation  rarely  exceeds 
4*2  cubic  feet  of  acetylene  per  pound  of  carbide  instead  of 
5  cubic  feet  per  pound. 

Probably,  therefore,  from  a  practical  point  of  view,  the 
generators  which  are  the  best  for  general  working  are  those  of 
the  second  class,  which  are  used  in  connection  with  a  holder  of 
sufficient  size  to  take  the  gas  evolved  from  the  full  charge  of 
carbide  employed. 

Approximately,  after  an  hour's  standing  each  kg.  of  calcic 
carbide  will  give  ten  litres  of  lime  sludge,  or  1  Ib.  of  carbide 
will  yield  eight  pints,  which  can  be  got  rid  of  by  a  sludge  cock 
at  the  bottom  of  the  apparatus. 

BLAU  GAS. 

This  gas  has  been  introduced  under  the  nama  of  the 
inventor,  Blau. 

c2 


20 


WELDING  AND  CUTTING  METALS 


It  is  liquefied  illuminating  gas  produced  by  distillation  of 
mineral  oils  in  red-hot  retorts.  Chemically  the  gas  consists 
of  the  same  elements  as  ordinary  coal  gas,  but  in  essentially 
different  proportions.  Blau  gas  is,  however,  free  from  carbon 
oxide,  and  has  therefore  the  advantage  over  coal  gas  of  not 
being  poisonous. 

The  analyses  give  the  following  compositions  of  the  Blau 
gas:  — 

One  litre  gas  (1*246  gr.)  contains,  at  0°  C.  and  760  m.m. 
barometer  pressure, 

1'042  gr.  carbon. 
0*204  gr.  hydrogen. 

Prom  the  absolute  weight  (1/246  gr.)  of  one  litre  the  specific 
weight  of  the  gas  is  found  to  be  0'963. 

The  number  of  calorics  was  found  to  be  12,318  per  one  kg., 
or  15,349  per  one  cubic  metre. 

By  comparison  of  equal  volumes  of  various  gases  in  respect 
of  heat  and  light  the  following  results  are  obtained : — 


Gas. 

Calorics  per  1  cb.  in. 

Candle  power. 
Hefner's  candles. 

Air  gas 

2,900 

500  incandescent 

Coal  gas 

5,000 

700  incandescent 

Acetylene    . 

13,000 

1,666  Hale  burner 

Blau  gas 

15,349 

3,000  incandescent 

Blau  gas 

12,318  per  1  kg. 

2,400  incandescent 

The  Blau  gas  can,  like  all  active  gases,  be  compressed  and 
liquefied,  and  in  this  latter  condition  it  occupies  ¥Jn  part  of 
its  gaseous  volume.  It  is  collected  in  the  ordinary  steel 
cylinders  for  transport,  the  smallest  cylinder  taking  0'49  litre 
or  0'25  kg.,  and  the  largest  49  litres  or  25  kg.  of  liquid  Blau 
gas  under  a  pressure  of  100  atmospheres. 

The  Blau  gas,  being  very  inert,  is  therefore  difficult  to  bring 


GASES  AND   SOURCES  FOR  THEIR  GENERATION       21 

to  explosion.  Its  extent  of  explosion  embraces  only  4  per  cent, 
(from  the  mixing  proportions  of  4  per  cent,  of  gas  and  96  per 
cent,  of  air  up  to  8  per  cent,  of  gas  and  92  per  cent,  of  air), 
while  that  of  coal  gas  is  13  per  cent,  (from  the  proportions 
of  6J  per  cent,  of  gas  and  93f  per  cent,  of  air  up  to  19J  per 
cent,  of  gas  and  80|  per  cent,  of  air),  and  that  of  acetylene 
47  per  cent,  (from  2  per  cent,  of  gas  and  98  per  cent,  of  air  up 
to  49  per  cent,  of  gas  and  51  per  cent,  of  air). 

HYDROGEN. 

This  is  an  elementary  gas  and  the  lightest  substance  known. 
It  is  colourless,  odourless,  and  non-poisonous,  although,  as 
ordinarily  prepared,  it  frequently  contains  traces  of  disagree- 
ably smelling  or  of  poisonous  impurities. 

Hydrogen  is  obtained  by  the  decomposition  of  water  in 
various  ways.  It  is  usually  prepared  by  the  action  of  zinc  or 
iron  on  a  solution  of  hydrochloric  or  sulphuric  acid.  AH 
metals  which  readily  decompose  water  when  heated  readily 
furnish  hydrogen  on  a  similar  treatment.  Many  other  acids 
may  be  used,  but  none  cut  more  readily.  In  all  cases  the 
action  consists  in  the  displacement  of  the  hydrogen  of  the 
acid  by  the  metal  employed,  and  if  the  acid  is  not  one  which 
can  enter  into  reaction  with  the  displaced  nitrogen,  the  latter 
is  evolved  as  gas. 

On  the  large  scale  mostly  pure  hydrogen  may  be  prepared 
by  passing  steam  over  charcoal  or  coke  heated  to  dull  redness. 
If  the  temperature  be  kept  sufficiently  low,  hydrogen  and 
carbon  dioxide  are  the  products  (C  +  2  H20  =  2  H2  +  CC^), 
and  the  latter  may  be  removed  by  causing  the  gas  to  traverse 
a  vessel  filled  with  slaked  lime. 

Hydrogen  is  also  obtained  pure  by  the  electrolytic  decom- 
position of  water,  as  described  under  the  heading  "  Oxygen  " 
on  page  27. 


22  WELDING  AND   CUTTING  METALS 

The  liquefaction  of  gaseous  hydrogen  is  an  achievement  the 
more  remarkable  as  it  was  the  result  of  the  simultaneous  but 
entirely  independent  labours  of  two  distinguished  physicists, 
Cailletet  of  Chatillon-sur- Seine  and  Rdoul  Pictet  of  Geneva — by 
the  former  on  the  30th  December,  1877,  and  by  the  latter  on 
the  10th  January,  1878. 

When  inhaled,  hydrogen  imparts  a  peculiar  squeaking  tone 
to  the  voice,  due  to  the  extreme  tenuity  of  the  gas  ;  small 
animals,  when  put  into  it,  die  instantly.  Hydrogen,  however, 
is  not  directly  poisonous,  hut  may  cause  death  by  preventing 
access  of  oxygen  to  the  lungs. 

Hydrogen  when  mixed  with  air  or  oxygen  is  explosive ;  the 
loudest  explosion  is  obtained  by  mixing  together  two  volumes 
of  hydrogen  and  one  volume  of  oxygen. 

Knowledge  and  Scientific  News,  in  its  October  number,  1908, 
refers  to  a  new  method  of  preparing  hydrogen  as  described  by 
Mauricheau-Bavpre  in  the  current  number  of  Cowptes  Rendns. 
A  coarse  powder  is  first  prepared  by  the  interaction  of  a  small 
quantity  of  mercuric  chloride  and  potassium  cyanide  with  fine 
aluminium  filings,  and  on  adding  water  to  the  resulting  com- 
pound in  the  proportion  of  one  litre  per  kg.,  hydrogen  is 
slowly  evolved,  the  oxidation  of  one  kg.  being  complete  in 
about  two  hours.  The  hydrogen  is  very  pure,  and  only  the 
simplest  apparatus  is  required  for  its  production.  Since  the 
powder  is  quite  stable  if  protected  from  moisture,  it  should 
form  a  useful  source  of  gas;  about  1,300  litres  may  be  obtained 
from  one  kg.  of  the  preparation. 

Hydrogen  is  also  obtained  in  large  quantities  as  a  by-pro- 
duct in  some  chemical  processes ;  for  instance,  in  Germany 
the  Badische  Anilin  und  Soda  Fabrik,  the  Chemische  Fabrik 
Griesheim,  and  the  Deutschen  Solvay  Werke  produce  annually 
twenty  to  twenty-five  million  c.m.  of  chemically  pure  hydrogen, 
which,  being  of  no  use  to  them,  is  simply  let  out  to  escape  in 


GASES  AND   SOURCES  FOR  THEIR  GENERATION       23 

the  air.  Ample  opportunity  is  therefore  given  to  find 
means  to  collect  and  utilise  such  an  enormous  quantity  of 
a  technically  useful  gas. 

OXYGEN. 

Oxygen  was  discovered  almost  simultaneously  in  the  year 
1774  by  Priestley  and  by  Sckeele,  the  Swedish  chemist  having, 
however,  nearly  completed  his  discovery  in  1772. 

Priestley  discovered  that  the  red  oxide  of  mercury  evolved 
a  gas  when  heated.  This  gas,  oxygen,  being  superior  even  to 
the  air  as  a  supporter  of  combustion,  was  regarded  by  him  as 
"  dephlogisticated  air."  The  incombustible  part  of  the  atmo- 
sphere he  supposed  to  be  saturated  with  phlogiston  on  the 
assumption  that  a  gas  was  so  much  the  better  adapted  for 
supporting  combustion,  as  it  contained  within  itself  a  smaller 
quantity  of  that  body,  common  air,  by  drawing  phlogiston 
from  burning  substances,  because,  as  he  thought,  phlogisti- 
cated  air  on  that  account  had  no  longer  any  attractions  for 
phlogiston,  or,  in  other  words,  any  power  of  supporting 
combustion. 

In  1789  Lavoisier 9  who  by  a  series  of  carefully  conducted 
and  very  ingenious  experiments  proved  that  the  combustion  of 
bodies  in  the  air  consisted  essentially  in  their  chemical  com- 
bination with  oxygen,  and  thus  overthrew  the  "  phlogiston  " 
theory,  gave  it  the  name  which  it  now  retains  (from  oxys  =  acid 
and  gennao  =  I  produce),  in  consequence  of  his  (erroneously) 
believing  that  it  was  a  necessary  constituent  of  every  acid. 

Oxygen  was  liquefied  in  1877  by  Pictet  at  a  pressure  of  320 
atmospheres  and  a  temperature  of  —  140°.  Wroblewski  and 
Olszewski  have  shown  that  the  critical  temperature  of  oxygen 
(i.e.,  the  temperature  above  which  no  amount  of  pressure  will 
liquefy  it)  is  —  113°,  the  pressure  needed  to  liquefy  it  at  that 
temperature  being  50  atmospheres.  Its  boiling  point  is  —  181*4 


24  WELDING  AND   CUTTING  METALS 

at  ordinary  pressure.  When  the  pressure  is  reduced  or 
removed,  evaporation  takes  place  so  rapidly  that  a  part  of  the 
oxygen  is  often  frozen  to  a  white  solid.  Under  13'7  atmo- 
spheres solidification  takes  place  at  —  146'8.  Sir  James  Deicar 
is  endeavouring  to  obtain'  liquid  oxygen  at  atmospheric 
pressure,  and  in  1892  he  devised  a  vacuum  vessel  for  con- 
taining liquid  oxygen. 

In  1808  Gay-Lussac  made  known  to  the  world  the  laws  of 
the  combination  of  gases  by  volume,  to  which  his  attention 
had  been  directed  by  the  discovery  which  he  and  Alex.  r. 
Humboldt  had  made  that  a  definite  volume  of  oxygen  com- 
bined with  exactly  twice  its  bulk  of  hydrogen.  He  pointed 
out  that  there  is  a  simple  relation  between  the  volumes  of  two 
gases  which  unite  together  and  also  between  their  collective 
volume  in  the  uncombined  and  in  the  combined  condition. 

According  to  the  law  of  Boyle  and  Mariotte  the  volume  of 
a  given  mass  of  any  gas  varies  inversely  as  the  pressure,  pro- 
vided that  the  temperature  remains  the  same ;  for  instance, 
the  quantity  of  air  which  is  contained  in  a  vessel  of  the 
capacity  of  one  pint  under  the  pressure  of  one  atmosphere,  or 
15  Ibs.  upon  the  square  inch,  may  be  contained  in  a  vessel  of 
half  a  pint  capacity  if  the  pressure  be  doubled. 

According  to  the  law  of  Charles  and  Gay-Lussac,  on  the 
other  hand,  all  gases  expand  equally  by  heat,  provided  the 
pressure  remains  constant,  the  rate  of  expansion  being  ^y^  of 
the  volume  at  0°  C.  for  each  rise  of  1°  C.  in  temperature  ;  or, 
in  other  words,  the  volume  of  a  gas  varies  directly  as  the 
absolute  temperature.  A  gas  which  strictly  conforms  to  these 
two  laws  is  said  to  be  a  perfect  gas,  but  none  of  the  gases  with 
which  we  are  acquainted  are  perfect  in  this  sense. 

From  the  few  accurate  observations  which  have  been  made 
on  this  subject  it  appears  that,  in  general,  the  departure 
from  the  laws  of  Boyle  and  Charles  is  greater  the  more  the 


GASES  AND    SOUECES  FOE  THEIE  GENEEATION        25 

temperature  of  the  gas  approaches  to  that  at  which  it  becomes 
liquid.  The  general  resemblance  in  the  behaviour  of  gases 
under  the  influence  of  pressure  and  heat  is  very  great, 
however. 

Numerous  processes  have  been  devised  for  the  industrial 
production  of  oxygen,  but  most  of  them  are  so  expensive,  or 
require  such  complicated  plants,  that  only  two  or  three  are  in 
actual  operation  on  a  large  scale. 

Brin's  process  of  producing  oxygen  by  the  alternate  forma- 
tion and  decomposition  of  barium  peroxide  is  an  improve- 
ment upon  the  Bausingault  process  of  1851  and  is  being 
worked  by  The.  British  Oxygen  Company,  Limited.  The  installa- 
tion of  the  plant  requires  a  considerable  space,  and  special 
heating  arrangements  are  required  underground  so  as  to  pro- 
duce a  working  temperature  of  some  800°  Fahr.  The  process 
must  be  worked  day  and  night,  as,  according  to  the  nature  of 
the  process,  the  oxidation  takes  place  every  five  minutes — that 
is  to  say,  no  oxygen  is  being  produced ;  besides,  the  furnace 
cannot  be  left  to  cool  during  the  night,  as  the  success  of  the 
process  depends  upon  certain  fixed  temperatures.  The  smallest 
change  in  temperature  in  the  furnace,  the  smallest  pollution 
of  the  air,  when  the  purifier  does  not  act  properly,  and  the 
baryte  itself  being  apt  to  change  entirely  in  the  furnace,  may 
produce  losses  of  considerable  extent  during  a  few  days'  time. 

Brin's  process  has  therefore  many  disadvantages,  and  its 
success  depends  upon  so  many  contingencies  that  it  cannot 
favourably  compare  with  other  processes  which  may  be  con- 
sidered safe  from  a  technical  point  of  view. 

The  Production  of  Oxygen  by  Electrolysis  of  Water  has  of  late 
found  considerable  extension,  although  it  was  considered  that 
the  inevitable  loss  attending  the  conversion  of  heat  into  power 
and  power  into  electrical  force,  and  the  need  of  skilled  labour, 
would  make  the  process  too  expensive. 


26  WELDING  AND  CUTTING  METALS 

Amongst  the  various  patents  five  different  processes  have 
found  practical  application,  viz.,  those  of  Garuti,  Schuckert, 
Dr.  Schmidt  (Zurich),  Hasard  Flamand,  and  Renard. 

All  these  processes  are  based  upon  the  decomposition  of 
alkaline  solutions  by  means  of  the  electric  current  liberating 
two  volumes  of  hydrogen  and  one  volume  of  oxygen  in  accord- 
ance with  the  formula  H20  =  2  HO.  They  differ,  however, 
in  the  type  of  electrodes  employed.  Schmidt  and  lienard  work 
with  porous  diaphragms  of  non-conducting  material,  while 
in  the  processes  of  Garuti  and  Schuckert  perforated  partitions 
of  a  conducting  material  are  used. 

Professor  Garuti  s  Process  having  many  advantages  is  there- 
fore described  here  :— 

The  principal  points  to  consider  are : 

1.  Reduction  to  a   minimum    of    the   electro-motive   force 
required,  and 

2.  Perfect  separation  of  gases  evolved. 

In  order  to  realise  the  first  condition  it  is  necessary  to  deter- 
mine the  most  favourable  composition  of  the  electrolyte,  that 
is,  the  liquid  to  be  decomposed,  and  the  proper  separation  of 
the  electrodes.  In  Fig.  1  the  electrodes  are  shown  to  be 
separated  by  the  porous  diaphragm  D,  but,  as  the  circulation 
of  the  electrolyte  is  essential  for  the  continuity  of  the  process, 
it  should  be  so  constructed  as  to  permit  this ;  in  order  to 
assure  the  separation  of  the  gases,  they  should  not  be  per- 
mitted to  pass  through  it,  but  to  reduce  the  resistance  the 
diaphragm  should  be  a  conductor. 

The  principal  conditions  required  of  a  perfect  diaphragm 
is  that  it  should  be  permeable  for  water,  impenetrable  for 
gases,  and  a  good  conductor  of  electricity.  It  is  evident  that 
the  construction  of  the  diaphragm  is  the  main  difficulty. 
Various  materials  for  the  same  have  been  employed,  such  as 
biscuit-baked  porcelain,  pipe  clay,  plates  of  carbon,  amianthus, 


GASES  AND   SOUECES  FOE  THEIE  GENEEATION        27 


Hydrogen 


FIG.  1. 


but  they  have  all  offered  disadvantages,  particularly  in  respect 
of  the  electrical  resistance  and  the  inability  of  preventing 
the  gases  to  pass  through. 

Garuti  has  suggested  the  application  of  metallic  diaphragms, 
which  also  have  been  found  to  give  satisfactory  results. 
If  a  metal  plate  is  placed  between 
the  two  electrodes  (Fig.  2)  it  is  T)  t 

influenced  by  the  current,  the 
positive  pole  formed  opposite  the 
negative  one  in  each  compart- 
ment, whereby  hydrogen  and 
oxygen  will  be  generated,  i.e., 
explosive  gas.  Garuti  has  dis- 
covered, however,  that  this  will 
not  take  place  if  the  electro- 
motive force  does  not  exceed 
three  volts  and  the  density  of 
the  current  remains  under  two 
amperes  per  square  decimetre  of 
electrode ;  under  such  circum- 
stances the  diaphragm  remains 
passive,  and  by  reason  of  its  low 
resistance  it  is  possible  to  work 
with  a  potential  under  three 
volts. 

It  remains  then  to  assure  the 
circulation     of    the     electrolyte.  FlG-  3> 

On  a  first  examination  it  is  found  that  the  better  the  circulation 
is  assured  the  less  is  the  resistance.  It  seemed  sufficient  to 
leave  a  space  between  the  diaphragm  and  the  bottom  of  the 
tank,  and  it  has  been  found  that  the  lower  edge  of  the 
diaphragm  should  not  reach  below  those  of  the  electrodes 
(Fig.  3).  A  mixture  of  gas,  however,  takes  place,  forming 


FIG.  2. 


28  WELDING  AND   CUTTING  METALS 

upon  the  electrodes  a  certain  volume  of  bubbles,  which, 
increasing  and  disengaging  themselves,  pass  direct  to  the 
surface.  Other  bubbles,  very  small,  almost  microscopical, 
detach  themselves,  as  soon  as  they  are  formed,  from  the 
electrodes  and  remain  in  suspension,  probably  by  reason  of 
their  extreme  tenuity,  and  darken  or  cloud  the  electrolyte, 
descend,  and  pass  under  the  electrodes,  turning  into  the 
neighbouring  compartment,  from  whence  the  mixture  of  gas. 
In  order  to  prevent  this  mixing  it  is  found  sufficient  simply  to 
lower  the  diaphragm  until  the  proper  resistance  has  been 
obtained. 

In  order  to  assure  the  circulation  of  the  electrolyte  the 
metallic  diaphragm  is  perforated.  Experience  has  proved 
that  these  perforations  can  have  a  diameter  up  to  one  m.m. 
each,  and  that  they  should  be  as  numerous  as  possible  and  be 
united  by  means  of  a  band  some  centimetres  high,  and  placed 
in  front  of  the  electrode.  Strangely  enough,  these  perforations, 
being  large  enough  to  circulate  the  electrolyte,  are  almost 
impermeable  for  the  gases,  probably  by  some  capillary  reason. 
The  metallic  diaphragms,  by  being  welded  together,  form 
cells  (Fig.  4),  each  containing  an  electrode,  and  fulfil  thereby 
every  condition  that  is  required. 

By  an  ingenious  arrangement  the  number  of  weldings  is 
reduced  to  a  minimum.  The  cells  of  the  apparatus  are  placed 
side  by  side,  with  their  lower  ends  open  entirely,  but  their 
upper  parts  open  about  half  their  length.  All  the  cells  con- 
taining an  anode  are  half  open  to  the  left  side,  and  those 
containing  a  cathode  are  half  open  to  the  right.  A  bell  or 
funnel  enclosing  the  left  ones  collects  oxygen,  and  a  similar 
funnel  containing  the  right  cells  collects  hydrogen  (Fig.  5). 
In  apparatus  of  certain  sizes  the  diaphragms  as  well  as  the 
electrodes  are  rigidly  kept  in  their  places  by  wooden  combs 
placed  at  their  lower  ends. 


GASES  AND  SOURCES  FOE  THEIR  GENERATION 


In  the  construction  of  the  apparatus  lead  is  used,  in  some 
special  cases,  with  an  electrolyte  composed  of  water  and  an 
acid,  but  in  general  iron  or  steel  is  used,  and  then  with  an 


A 


i 


FIG.  4. 


A 


A 


1 


FIG.  5. 


electrolyte  composed  of  a  solution  of  soda  or  caustic  potash ; 
the  latter  presents  a  smaller  resistance,  but  is  more  expensive. 
The  solution  has  a  minimum  resistance  of  15  per  cent,  for 
soda,  but  generally  25  per  cent.,  and  29  per  cent,  for  potash. 


30  WELDING  AND   CUTTING  METALS 

In  order  to  facilitate  the  liberation  of  the  gas  bubbles  and  to 
avoid  their  passing  through  the  perforated  diaphragms  the 
solution  should  be  very  concentrated. 

The  iron  is  not  quite  indifferent  to  the  action  of  the  alkali, 
and  Professor  Eric  Gerard  has  found  the  wear  and  tear  of  the 
anodes  in  Garutis  apparatus  to  amount  to  15  per  cent,  of 
,  the  weight  of  the  anode.  In  practice  the  anodes  have  a 
thickness  of  0*7  millimetre  at  the  beginning,  and  require  to  be 
exchanged  after  every  three  years'  working ;  consequently  a 
very  small  loss;  otherwise  the  apparatus  offers  no  alteration, 
the  electrolyte  does  not  change;  should  it,  however,  in  length 
of  time  become  highly  carboniferous,  it  is  easy  to  generate  the 
feolution  by  some  lime.  The  anodes  as  well  as  the  wooden 
combs  require  to  be  exchanged  every  three  years;  the  costs  of 
maintenance  are  therefore  practically  nil. 

The  generators  work  without  intervention  of  manual  labour, 
and  they  are  arranged  side  by  side  in  a  room  having  a  con- 
stant temperature ;  the  gases  produced  are  collected  in  iron 
piping  and,  after  passing  through  a  regulator,  enter  the 
gasometers.  The  attendance  is  limited  to  refilling  each  of 
the  generators  with  three  to  four  litres  of  water  per  day.  In 
respect  of  safety  it  is  advisable  frequently  to  analyse  the  gases, 
easily  done  by  HempeVs  apparatus  or  by  Bassanis  electric 
density  meter,  or  still  better  by  an  aerostatic  scale,  which  has 
the  advantage  of  giving  continuous  indications. 

In  reference  to  the  commercial  point  it  is  well  to  remember 
that  one  coulomb  liberates  0*0829  milligramme  of  oxygen  and 
0*703  milligramme  of  hydrogen,  or  0*058  cubic  centimetres 
of  oxygen  and  0*116  cubic  centimetres  of  hydrogen  at  a 
temperature  of  0°  C.  and  at  a  pressure  of  760  millimetres,  i.e., 
atmospheric  pressure. 

One  ampere-hour  liberates  208*8  cubic  centimetres  of  oxygen 
and  417*6  cubic  centimetres  of  hydrogen  under  the  same 


GASES  AND   SOUECES  FOE  THEIE   GEXEEATION        31 

conditions  in  respect  of  temperature  and  pressure.  As  the 
operation  generally  takes  place  at  a  temperature  of  15°  to  20°  C., 
it  may  be  admitted,  for  practical  purposes,  and  taking  account 
of  all  the  losses,  that  one  ampere-hour  will  give  0*40  litres  of 
hydrogen  and  0*20  litres  of  oxygen. 

As  to  the  electro-motive  force  required, 

One  gramme  of  water  releases,  in  its  formation,  about  3*8 
calorics,  or  3'8  X  425  =  T615  kilogramme  metres. 

One  coulomb  decomposes  0*0000933  gramme  of  water  ;  in 
order  to  decompose  one  gramme  of  water  an  expenditure  in 

work  is  therefore  required  represented  by  C    X   X 

u 


1  x  X 

volts,  or,  expressed  in  kilogramme  metres, 


0-0000933  X  9*81' 
Y 

or,  as  above  stated,  Q.QQQQ933  x  9-81  =  1*615,  thus  X  =  1-488, 

or  in  round  figures  1'5  volts.  Gerard  has  found,  however,  that 
the  electro-motive  force  required  by  a  Garuti  apparatus  made 
of  steel,  with  an  electrolyte  of  caustic  potash  as  pure  as  possible, 
amounts  to  T988  volts.  But  for  industrial  purposes  it  is  not 
possible  to  go  as  low  as  that ;  with  an  electrolyte  composed 
of  caustic  soda  an  electro-motive  force  of  2'4  volts  is  required, 
while  with  potash  it  may  be  reduced  to  2*2  volts. 

Assume,  however,  a  voltage  of  2'4  at  the  most,  and  a  pro- 
duction of  0*40  litre  of  hydrogen  and  0*20  litre  of  oxygen  per 
ampere-hour,  the  production  per  kilowatt-hour  amounts  to — 
Hydrogen,  166'6  litres,  equal  to  37  gallons, 
Oxygen,          83'3  ;  „  „       18'5     „ 

or  250  litres  =  55*5  gallons  of  explosive  gas. 

The  production  of  one  cubic  metre  of  explosive  gas  (666  litres 
hydrogen  and  333  litres  oxygen)  requires  thus  4  kilowatts. 

One  cubic  metre  of  hydrogen  alone  requires  6  kilowatts. 

One     „         „        „  oxygen         ,,  „         12 


32  WELDING  AND   CUTTING  METALS 

Assuming  a  minimum  voltage  of  2*2,  the  production  per 
kilowatt-hour  would  be — 

Hydrogen    .                           ...     181/8  litres 
Oxygen 90*9     „ 

The  production  of  one  cubic  metre  explosive  gas  requires 
3*667  kilowatts,  one  cubic  metre  of  hydrogen  alone  5*50 
kilowatts,  and  one  cubic  metre  of  oxygen  alone  11*00  kilowatts. 
Finally,  the  gases  produced  are  practically  pure  ;  the  hydrogen 
contains  an  appreciable  quantity  of  other  gases,  while  the 
oxygen  contains  J  to  4  per  cent,  of  hydrogen,  which  can  easily 
be  removed. 

The  Production  of  Oxygen  from  Liquid  Air. — It  has  already 
been  mentioned  on  page  7  that  oxygen  is  produced  through 
the  liquefaction  of  atmospheric  air,  principally  by  Linde, 
Knudsen,  and  Claude. 

Linde  has,  as  the  pioneer,  by  his  strenuous  efforts  and  scien- 
tific demonstrations  created  a  new  industry,  which  becomes 
more  and  more  important  by  the  extension  of  the  practical 
applications  of  its  products,  oxygen  and  nitrogen.  The 
patents  for  the  United  Kingdom  have  been  acquired  by  The 
British  Oxygen  Company,  Limited,  which  have  works  in  London, 
Manchester  and  Birmingham  producing  oxygen  of  any  required 
purity.  The  Linde  system  is  simple  and  continuous ;  the  plant 
may  be  erected  almost  anywhere  without  restrictions,  requiring 
but  a  small  space. 

The  Knudsen  patents  for  the  United  Kingdom  are  owned  by 
The  Liquid  Air  Power  and  Automobile  Company  of  Great 
Britain,  Limited,  having  a  250  h.p.  plant  working  at  Battersea, 
London. 

The  Claude  system  is  being  worked  principally  in  France, 
represented  in  the  United  Kingdom  by  The  British  Liquid 
Air  Company,  Limited. 

As  to  the  cost   of  production   of    oxygen    by    the   various 


GASES  AND   SOURCES  FOR  THEIR   GENERATION        33 

systems,  it  is  difficult  to  give  exact  figures,  but  the  following 
statements  have  been  obtained  so  far  as  the  cost  of  the 
machines  is  concerned,  in  addition  to  which  must  be  con- 
sidered the  spaces  required,  maintenance  of  plant,  and  other 
more  or  less  important  points  bearing  upon  the  question. 

Assuming  a  production  of  250  cubic  metres  of  oxygen  per 
twenty-four  hours,  the  cost  of  the  plants  actually  required  for 
the  production  of  the  oxygen,  but  without  cost  of  erection  and 
of  the  compressors  required  for  the  compression  of  the  gas, 
has  been  given  as  follows  :— 

Brin's  process     .         .         .         .         .      £2,900 
Garuti's  electrolytic  process         .         .         4,000 
Linde's  system    .....         2,350 
The    cost  per  cubic  metre  is  given  by    Linde's   system  at 

12*7  pfg. ;   Garatis  system  at  8  pfg. 

When  the  annual  consumption  exceeds  5,000  cubic  metres, 
or  when  the  reduction  in  price  would  increase  its  application 
to  welding  and  cutting,  then  it  would  be  advisable  to  produce 
oxygen  at  the  place  of  operation.  Oxygen  is  a  gas  which  can 
easily  be  produced  at  any  place  in  similar  manner  as  ordinary 
coal  gas.  By  so  doing  its  price  would  be  materially  reduced. 
The  oxygen  used  for  welding  must  be  free  from  chlorine, 
while  its  usual  mixture  with  5  per  cent,  of  nitrogen  and  2  to 
3  per  cent,  of  hydrogen  is  of  no  importance. 

WATER  GAS. 

Lavoisier  discovered  in  1793  that  when  steam,  unmixed 
with  air,  is  passed  through  glowing  coke,  the  coke  is  oxidised ; 
carbonic  oxide  and  hydrogen  are  produced  theoretically  pure, 
and  in  equal  volumes  ;  practically  the  product  contains  3  to  8 
per  cent,  of  carbonic  acid  and  4  to  9  per  cent,  of  nitrogen. 
The  yield  is,  from  coke  (7,000,000  calorics  per  ton),  about 
35,000  cubic  feet,  with  a  heating  value  of  about  75,000  calorics 

w.  D 


34  WELDING  AND   CUTTING   METALS 

per  1,000  cubic  feet,  or,  on  the  whole,  about  40  per  cent  of  the 
heat  value  of  the  coke ;  from  coal  (7,800,000  calorics  per 
ton),  about  42,000  cubic  feet  at  95,000  calorics,  or  about 
49  per  cent. 

When  the  by-product — "  the  producer  gas  "  —which  may  be 
generated  in  large  quantities  by  regulating  the  supply  of  air 
while  the  coke  glow  is  being  worked  up,  is  used  for  boilers 
or  gas  engines,  the  net  cost  of  making  simple  water  gas 
is  between  5d.  and  6d.  per  1,000  cubic  feet,  or  about  Sd.  per 
1,000  less  than  coal  gas. 

Water  gas  gives  on  combustion  an  extremely  high  tempera- 
ture, which  saves  time  in  furnace  work ;  gold,  silver,  and 
copper,  and  even  an  alloy  of  70  per  cent,  of  gold  and  30  per 
cent,  of  platinum,  are  readily  melted  in  quantity  by  it ;  hence 
for  bringing  objects  such  as  Fahnehjelms  combs  (a  series  of 
rods  of  magnesia)  into  brilliant  luminous  incandescence,  for 
welding  or  for  metallurgical  operations  inducing  high  tem- 
perature, it  is  very  suitable.  Unfortunately,  its  high 
percentage  of  carbonic  oxide,  which  is  odourless,  has  caused 
a  high  death  roll. 


CHAPTEE  III 

WELDING 

Description — Different  Systems — Acetylene  Welding — Aluminium  Weld- 
ing— Aluminium  Thermic  Welding — Blau  Gas  Welding — Chemical 
Welding — Coal  Gas  Welding — ElectricWelding — Forging — Hydrogen 
Welding— Water  Gas  Welding. 

DESCRIPTION  OF  WELDING. 

WELDING  is  the  intimate  union  produced  between  the  sur- 
faces of  two  pieces  of  metal  when  heated  to  proper  temperature 
and  hammered  together.  The  union  is  so  close  that  when 
two  bars  of  metal  are  properly  welded  the  place  of  junction 
is  as  strong  relatively  to  its  thickness  as  any  part  of  the  bar. 
To  weld  bar  iron  to  another  piece  of  iron  requires  an  intense 
heat.  Wrought  iron  at  the  welding  temperature  possesses 
the  property  of  expanding  when  cooled  and  contracting  when 
heated,  and  the  welding  property  is  intimately  connected  with 
the  critical  condition  in  which  this  abnormal  behaviour  is 
exhibited. 

The  condition  known  as  "  the  welding  state  "  of  iron  or 
steel  is  one  which  exists  only  within  a  very  limited  range  of 
temperature.  If  the  smith  takes  his  iron  bars  out  of  the  fire 
at  too  low  a  temperature,  welding  cannot  be  effected.  If,  on 
the  other  hand,  the  iron  is  too  hot,  a  failure  is  also  certain. 

The  range  of  temperature,  during  which  impact  or  pressure 
causes  the  union,  known  as  welding,  of  two  masses  of  iron  or 
steel,  is  therefore  comprised  within  narrow  limits,  and  the 
familiar  operation  is  really  a  critical  one. 

In  welding  by  the  forging  process  the  parts  to  be  united  are 

D2 


36  WELDING  AND   CUTTING  METALS 

heated  within  the  critical  range  of  temperature,  considerably 
less  than  that  of  fusion.  The  smith  in  striking  with  his 
hammer  is  assisted  by  the  molecules  which  approach,  though 
never  arrive  at,  liquidity.  This  condition  is  favourable  to  the 
interpenetration  of  the  molecules  and  consequent  adhesion 
of  the  surfaces  on  hammering. 

It  has  been  shown  by  Sir  Thomas  Wriglitson  that  the 
phenomenon  of  welding  is  akin  to  that  of  regelation,  or  the 
sticking  together  of  ice  under  pressure.  To  prove  this  an 
experiment  was  made  which  showed  a  distinct  decrease  in 
temperature,  amounting  to  106°  F.,  at  2,550°  F.  during 
welding,  a  similar  result  being  known  to  take  place  during 
regelation.  This  abstraction  of  heat  is  caused  by  the  melting 
of  the  iron  or  ice  in  either  case,  and  the  consequent  need  of 
latent  heat  for  the  liquefaction. 

If  the  welding  of  two  metals  is  caused  by  fusion  by  the  aid  of 
combustible  gases  in  conjunction  with  oxygen,  this  latter  acting 
as  the  gas  of  combustion,  or  by  electricity,  or  even  by  the 
Alumino-Thermic  process,  the  metals  become  subject  to  con- 
siderable alteration  in  their  properties  chemically  as  well  as 
physically,  offering  thereby  difficulties  of  great  extent  in  the 
production  of  a  perfect  weld. 

The  welding  by  aid  of  combustible  gases  is  very  similar  to 
casting ;  and  if  it  may  be  termed  a  process  of  casting,  then  also 
must  the  conditions  attributed  to  that  process  be  applicable  to 
welding  more  or  less.  The  difference  would  then  appear  to 
be  the  composition  of  the  moulds,  those  of  sand  being  substi- 
tuted by  the  metal  to  be  welded,  which,  however,  is  of 
superior  and  more  finished  make  as  compared  with  the  metal 
to  be  used  for  the  completion  of  the  \veld.  The  molten  or 
liquefied  metal  is  poured  at  a  considerable  temperature  into 
the  grooved  metal  pieces  to  be  welded,  which  have  the 
temperature  of  the  surrounding  atmosphere  only,  and  is  then 


WELDING  37 

subjected  to  a  mechanical  treatment,  in  order  to  increase  the 
strength  and  ductility  of  the  weld  so  that  it  may  resemble  thai; 
of  wrought  iron  more  or  less. 

Although  the  cast-iron  expands  at  the  moment  of  solidifica- 
tion and  thus  seemingly  produces  a  weld,  the  subsequent 
cooling  from  a  red  heat  to  the  ordinary  temperature  leads  to 
a  still  greater  contraction,  and  the  net  result  is  an  imperfect 
weld.  To  overcome  this  difficulty,  mechanical  means  must 
be  employed  to  facilitate  the  union  between  the  molten  mass 
and  the  metals,  converting  the  former,  as  far  as  possible,  into 
a  similar  condition  to  that  of  the  superior  metal.  The  con- 
traction that  takes  place  during  cooling  after  solidification  is 
not  uniform,  but  is  interrupted  by  certain  arrests  or  expan- 
sions which  occur  at  particular  temperatures.  The  shrinkage 
in  welds  is,  however,  by  no  means  a  constant  quantity,  but 
varies  with  the  proportions  of  the  weld  and  with  the  character 
of  the  metal  used. 

The  strength  and  solidity  of  the  weld  are  affected  by  the 
bulk  of  metal  employed  to  complete  the  weld,  and  also  by  the 
form  of  the  article  to  be  welded.  Thus,  if  a  sample  of  cast-iron 
which  would  be  suitable  for  a  weld  of  small  size  be  employed 
for  making  a  very  heavy  weld,  it  will  be  found  that,  owing  to 
the  slower  cooling  in  the  latter  case,  the  grain  of  the  metal 
becomes  much  more  open,  and  the  strength  is  proportionately 
diminished.  On  the  other  hand,  if  the  same  metal  were  used 
for  very  small  welds,  the  chilling  in  the  seam  or  groove  of  the 
weld  would  tend  to  make  the  product  close  and  hard,  and  in 
many  cases  this  would  be  so  marked  as  to  make  the  weld 
quite  brittle.  The  grade  of  the  iron  used  must  therefore  depend 
upon  the  size  of  the  weld  to  be  made,  and  probably  a  closer 
grained  iron  must  be  used  for  large  than  for  small  welds.  At  the 
same  time,  it  is  generally  found  that  the  strength  of  a  large 
weld  per  unit  of  area  is  somewhat  less  than  that  of  a  smaller 


38  WELDING  AND   CUTTING  METALS 

one,  since  the  closeness  of  grain  is  usually  though  not  always 
associated  with  increased  tenacity. 

It  is  also  very  important  that  in  large  welds,  where  strength 
is  required,  no  sharp  or  re-entering  angles  should  occur,  as 
these  in  all  cases  lead  to  the  formation  of  planes  of  weakness 
in  the  weld.  When  the  metal  cools  in  the  weld  a  crystalline 
structure  is  developed,  the  crystals  forming  at  right  angles 
to  the  cooling  surface.  If  this  cooling  surface  be  curved, 
the  crystals  interlace  so  as  to  yield  a  strong  weld  of  uniform 
structure,  while  on  the  other  hand,  whenever  a  sharp 
change  of  curvature  takes  place  a  plane  of  weakness  is  the 
result. 

It  is  much  to  be  desired  that  some  plan  could  be 
adopted  by  which  a  test  piece  weld  would  indicate  exactly 
and  directly  the  physical  qualities  of  a  weld  of  the  same  metal, 
but  no  method  of  doing  this  has  been  devised  or  seems  likely 
to  be. 

Until  it  has  been  fully  made  clear  what  takes  place  during 
the  operation  of  autogenous  welding,  the  changes  that  take 
place  in  the  chemical  as  well  as  the  physical  compositions  not 
only  of  the  metal  parts  to  be  welded  together,  but  also  of  the 
liquefied  metal  which,  from  the  welding  bar  is  poured  into 
the  seam  of  the  weld,  and  more  so  the  intermediary  and  gradual 
interlacing  action  upon  the  two  metals,  it  seems  useless  as  well 
as  fruitless  to  discuss  what  kind  of  repairs  may  or  may  not  be 
made  especially  upon  marine  boilers,  so  as  to  satisfy  not 
merely  the  insurance  inspectors  but  to  a  greater  extent  to 
secure  that  safety  in  public  conveyance  which  is  of  vital 
importance. 

Discussion  and  professional  examination  in  this  direction 
would  tend  more  quickly  to  solve  the  difficulties  so  vividly 
apparent  in  the  great  and  important  industry  of  autogenous 
welding. 


WELDING  39 

DIFFERENT  SYSTEMS  OF  WELDING. 

Welding  may  be  accomplished  by  various  means,  and  the 
different  systems  employed  may  be  divided  into  two  main 
divisions  : 

The  Autogenous  Welding,  by  means  of  which  the  fusion  or 
union  of  the  metals  is  obtained  direct,  without  the  intermediary 
of  any  foreign  material. 

The  Heterogeneous  Welding,  in  which  an  additional  foreign 
metal  or  alloy  is  introduced,  the  melting  point  of  which  is 
below  that  of  the  metals  to  be  welded. 

The  autogenous  welding  is  especially  applicable  to  iron, 
steel  and  lead,  while  the  heterogeneous  welding  is  indis- 
pensable, or  almost  so,  for  zinc,  brass,  and,  up  to  recently,  also 
for  aluminium,  or,  generally,  for  those  metals  which  oxidise 
or  volatilise  at  a  temperature  near  that  of  the  point  of  fusion. 

In  the  autogenous  welding  of  iron  and  steel  two  distinct 
processes  may  be  distinguished  : — 

The  Forging  Process,  which  is  based  upon  the  property 
possessed  by  iron  to  become  doughy  or  plastic  at  a  temperature 
considerably  below  that  of  fusion. 

The  Welding  by  Fusion,  which  is  carried  out  by  means  of 
compressed  gases  and  blowpipes. 

The  other  processes  which  have  recourse  to  fusion  of  the 
metal,  and  are  therefore  also  designated  under  the  name  of 
autogenous  welding,  are  : — 

The  Alumino- Thermic  Process. 

The  Electric  Welding. 

The  Aluminium  Welding. 

The  welding  by  means  of  compressed  gases  is  generally 
effected  by  a  mixture  of  various  gases,  amongst  which 
oxygen  plays  the  most  important  part,  as  being  the  gas  of 
combustion. 


40 


WELDING  AND  CUTTING  METALS 


The  various  welding 
systems  are  generally  recog- 
nised under  the  name  of  the 
combustible  gas  employed, 
as  follows  : — 

The  Acetylene  welding. 

The  Blau-gas  welding. 

The  Coal-gas  welding. 

The  Hydrogen  welding. 

The  Water-gas  welding. 

Most  of  the  combustible 
gases  employed  are  gene- 
rated by  automatic  or  non- 
automatic  plants,  and  the 
gases  may  be  used  under 
low  or  high  pressure. 

A  description  of  each 
welding  system  will  be  given 
below. 

ACETYLENE  WELDING. 

In  the  case  of  automatic 
or  non-automatic  welding 
plants  the  gas  from  the 
generator  A  passes  into  a 
condenser  to  cool  it  and  to 
remove  any  tarry  products  ; 
it  enters  thereafter  a  wash- 
ing apparatus  B,  filled  with 
water,  to  extract  water- 
soluble  impurities ;  from 
thence  it  travels  to  the 
gasometer  C.  In  leaving,  the  gasometer  the  acetylene  passes 


WELDING  41 

to  the  purifier  D,  and  travels  from  there  through  ordinary 
mains  E  to  a  back-pressure  hydraulic  valve  F.  It  is  then 
ready  to  be  drawn  from  these  into  the  blowpipe  G. 

The  oxygen,  compressed  into  the  cylinder  H,  passes  into 
the  pressure  regulator  J ;  a  rubber  tube  K  leads  it  from  there 
into  the  blowpipe  G,  where  it  is  mixed  with  the  acetylene 
before  the  two  gases  leave  the  nozzle,  in  order  to  effect  the 
welding  of  the  plates  L. 

If  the  generator  is  of  the  carbide-to-water  type,  the  con- 
denser may  be  omitted,  and  the  washer  is  required  to  retain 
any  lime -froth. 

Any  number  of  blowpipes  can  be  worked  from  these  mains 
M,  but  at  each  point  where  gas  will  be  used  for  a  blowpipe  a 
back-pressure  hydraulic  valve  must  be  fixed. 

EEGULATORS. 
Hydraulic  Pressure-Regulating  Valve. 

The  back-pressure  hydraulic  valve  precludes  the  possibility 
of  oxygen  at  any  time  flowing  into  the  gasholder  and  also  air 
from  being  drawn  into  the  acetylene  mains.  Its  action,  illus- 
trated by  Fig.  7,  is  as  follows : — 

The  acetylene  pipe  from  the  gas-holder  is  connected  to  the 
branch  /,  and  the  acetylene  pipe  leading  to  the  blowpipe  is 
connected  to  the  branch  d.  Water  is  poured  into  the  open 
chamber  b  until  it  reaches  the  closed  vessel  a. 

The  valve  is  then  in  working  order.  The  filling  pipe  c 
is  made  long  enough  to  hold  a  column  of  water  equal  to  the 
pressure  of  the  acetylene  holder,  which  should  be  about 
9  in.  of  water.  The  supply  of  acetylene  to  the  blowpipe 
may  be  regulated  by  the  tap  on  the  branch  d  (where  taps  do 
not  exist  on  the  blowpipe  itself),  and  the  tap  at  /  may  be 
left  permanently  open. 


42 


WELDING  AND  CUTTING  METALS 


Should  the  blowpipe  nozzle  at  any  time  become  choked 
whilst  the  oxygen  supply  remained  unchecked  this  gas  would 
be  forced  by  its  superior  pressure  along  the  acetylene  pipe. 
The  back  pressure  thus  caused  acting  on  the  surface  of  the 
water  in  the  chamber  a  would  force  this  water  up  the  pipe  e, 


Fig.l 


'Ci 


Fig.  2 


Fig.3 


i  a 


Ci 


-i  a 


s  c 


EiG.  7. — Draeger's  Patent. 

and  prevent  the  oxygen  from  entering  the  acetylene  supply 
pipe  beyond  the  tap  of  the  hydraulic  valve. 

High-Pressure  Automatic  Regulator  (Fig.  8). — This  is  an  auto- 
matic regulator  which  is  made  to  deliver  gas  at  any  required 
pressure  up  to  about  30  Ibs.  per  square  inch.  The  pressure 
can  be  adjusted  by  unscrewing  the  screw  E  for  low  pressure, 
or  by  screwing  down  E  for  high  pressure.  The  indicator  M 


WELDING 


43 


M 


indicates  the  pressure  of  delivery  as  set  by  E.     The  maximum 

pressure  at  which  the  regulator 

will   work  is   marked  by  a   red 

line   on  the  indicator  M,  and  if 

this    pressure    is    exceeded    (by 

•screwing    E    too    far)    a    safety 

valve   S   will  open   and   release 

the  excess  pressure.     The  tap  H 

lor  controlling  the  supply  is  a 

•convenience    which    the     safety 

valve  S  renders  possible.     N  is 

the   delivery    nozzle,   and    F   is 

a  gauge  for  registering  pressure 

of  gas  in  cylinder.  This  regu- 
lator is  extensively  used  in  blow- 
pipe work. 

High-Pressure  Automatic  Regu- 
lator   (Fig.    9)    (Patent).  —  This 

regulator,  fitted  with  or  without  high-pressure  gauge,  possesses 

exactly  the  same  features  as  the 
one  in  the  preceding  illustration .  It 
is  suitable  for  every  class  of  work. 
It  is  of  substantial  construction, 
and  has  been  specially  designed  for 
workshop  use.  It  is  specially  re- 
commended for  all  kinds  of  blow- 
pipe work.  The  adjustable  screwed 
socket  on  the  side  of  the  regulator 
is  graduated  in  pounds  per  square 
inch,  and  the  regulator  can  be  set 
by  this  means  to  any  desired 
constant  pressure,  thus  enabling 

the  usual  low-pressure  gauge  to  be  dispensed  with. 


FIG.  8. 


FIG. 


WELDING  AND   CUTTING  METALS 


FIG.  10. 


Gas  Pressure  Gauge  (Fig.  10). — These  pressure  gauges  are 
useful  to  frequent  users  of  oxygen  cylinders,  and  particularly  to 
agents,  as  a  means  of  ascertaining  the  quantity 
of  gas  in  cylinders. 

The  gauges  as  illustrated  are  specially  marked 
in  atmospheres  and  feet,  and  the  cubic  contents. 
of  any  cylinder  may  be  readily  calculated  in  the 
following  manner  :— 

The  figures  on  outer  ring  indicate  pressure 
in  atmospheres ;  120  atmospheres  being  the 
pressure  to  which  all  cylinders  are  charged. 

The  figures  on  inner  ring  indicate  the  number 
of  cubic  feet  of  gas  contained  in  a  10-foot  cylinder.      To  calcu- 
late the  quantity  of  gas  contained  in  any  cylinder,  multiply 
the  figure  to  which  the  needle  points  by  the  multiple 
of    10  ;    thus,  if  the  gauge  is  attached  to   a  40-foot 
cylinder,  and  the  needle  points  to  6,  then  6X4  = 
24  feet  =  quantity  of  gas  in  cylinder. 

Both  types  of  pressure  gauge  are  fitted  with  safety 
checks  in  the  stem  to  prevent  a  sudden  rush  of  gas 
into  the  gauge  tube  when  the  cylinder  valve  is  opened. 
Leak  Tester  (Fig.  11). — To  use  the  tester.  Press  the 
conical  rubber  end  into  the  outlet  of  the  cylinder  valve. 
If  there  is  the  slightest  leakage  of  gas  it  will  be  at  once 
indicated  by  bubbles  passing  through  the  water.  If, 
on  the  other  hand,  there  is  no  leakage,  bubbles  will 
not  be  perceptible. 

The  instrument  is  a  handy  substitute  for  the  clumsy  method 
of  testing  for  leakage  by  pouring  some  water  into  the  socket  of 
the  valve.  It  is  only  about  4  inches  long,  and  can  be  carried 
in  the  waistcoat  pocket.  The  water  is  found  to  evaporate  very 
slowly,  and  will  only  require  renewal  at  long  intervals  of  time. 
N.B. — Oil  must  not  be  used  in  the  tester. 


FIG.  11. 


WELDING 


45 


Steel  Cylinders  (Fig.  12). — All  cylinders  sold  or  employed  by 
the  British  Oxygen 
Company  are  guaran- 
teed to  be  made  of  steel 
complying  with  the 
British  Government 
recommendations. 
They  are  made  to  the 
company's  own  specifi- 
cations, and  are  regu- 
larly inspected  during 
manufacture  by  one  of 
the  company's  engi- 
neers. They  are  all 
re-annealed,  valved, 
and  tested  hydrauli- 
cally  to  a  pressure  of 
1J  tons  per  square 
inch,  in  the  company's 
works,  before  being 
filled  with  gas.  The 
company's  methods  of  ^is.  12.-Trolley  Stand  for  Pair  of  Cylinders. 

annealing,  testing  and  filling  cylinders  are  in  accordance  with 
the  British  Government  recommendations. 


*Cubic  contents  in 
feet  fully  charged. 

Approximate 
external  diameter 
in  inches. 

Approximate  length 
over  all  in  inches 
including  valve. 

Approximate  weight 
in  Ibs.  (empty). 

10 

4 

19 

13 

20 

4 

35 

23 

40 

5J 

36 

43 

60 

7^ 

32 

66 

80 

7 

41 

85 

100 

7 

49 

103 

All  oxygen  cylinders  are  filled  to  120  atmospheres  pressure 


46 


WELDING  AND   CUTTING  METALS 


Annealing. — In  accordance  with  Government  recommenda- 
tions, all  cylinders  (before  being  subjected  to  the  usual 
hydraulic  test  for  the  first  time)  must  be  annealed.  All 
cylinders  received  at  the  company's  works  to  be  filled  for  the 
first  time  will,  after  annealing,  be  tested  hydraulically  to  a 
pressure  of  1J  tons  per  square  inch,  and  afterwards  registered. 
The  company  re-test  all  cylinders  annually,  a  periodical  re-test 

being  necessary  as  much 
in  the  interest  of  the 
customer  as  of  the 
company. 

All  hydraulic  testing 
of  cylinders  is  done  by 
the  company  in  their 
stretch  testing  appa- 
ratus (Fig.  13).  This, 
system  was  first  intro- 
duced by  the  British 
Oxygen  Company 
twenty  years  ago.  It 
was  officially  approved 
by  the  British  Govern- 
ment's Cylinder  Com- 
mittee of  1896,  and  has 
recently  been  added  to 


FIG.  13.— Stretch  Testing  Apparatus  for 
Cylinders. 


the  official  Cylinder  Eegulations  of  Germany  and  other 
countries.  Being  an  apparatus  of  general  interest  it  is  now 
illustrated  and  described  below  : — 

This  apparatus  consists  of  a  cast-iron  chamber  B,  in  which 
the  cylinder  A  to  be  tested  is  suspended.  D,  an  hydraulic 
pump  employed  for  testing  the  cylinder  A.  E,  a  gauge  glass 
communicating  with  the  bottom  of  chamber  B ;  and  C,  an 
indiarubber  joint  ring,  which  is  capable  of  closing  and  making 


WELDING 


47 


a  perfect  joint  round  the  shoulder  of  the  cylinder.  The 
method  of  testing  is  as  follows : — -Both  cylinder  A  and 
chamber  B  are  filled  with  water  to  the  exclusion  of  all  air, 
and  a  perfect  joint  is  made  round  the  neck  of  the  cylinder  by 
inflating  the  indiarubber  ring  C,  which  can  be  instantaneously 
done  by  water  pressure  from  the  ordinary  main  supply.  When 
the  cylinder  is  gradually  subjected  to  the  test  pressure  by 
means  of  the  pump  D,  its  expansion  is  measured  by  the 
displacement  of  water  from  the  chamber 
B,  and  this  displacement  is  indicated  by 
the  rise  of  the  water  level  in  the  gauge 
glass,  which  continues  until  the  maxi- 
mum test  pressure  is  obtained.  The 
pressure  is  then  released,  and  if  no  per- 
manent stretch  has  been  given  to  the 
metal,  the  water  will  return  to  its 
original  level  in  the  indicator.  If,  how- 
ever, any  permanent  stretch  has  been 
caused  this  will  not  be  the  case,  and  the 
cylinder  would  therefore  be  rejected  as 
unfit  for  use. 

The  value  of  this  apparatus  is  obvious. 
Its  employment  insures  that  a  cylinder 
is  never  strained  beyond  the  "  elastic  limit "  of  its  metal,  and 
without  this  safeguard  no  hydraulic  test  is  reliable. 

In  blowpipe  work  the  only  object  of  a  combined  regulator 
and  high-pressure  gauge  is  to  guard  against  the  oxygen  supply 
running  short  in  the  middle  of  a  job.  Pressure  gauges  per- 
manently attached  to  regulators  are  a  fruitful  source  of  trouble. 
They  soon  become  inaccurate  (particularly  the  small  type  so 
frequently  employed)  and  being  delicate  in  construction  they 
are  liable  to  injury  in  workshop  handling.  The  connector 
(Fig.  14)  is  an  excellent  substitute  for  the  pressure  gauge 


FlG.  14. — Connector 
between  Eegulator 
and  two  Cylinders. 


48 


WELDING  AND   CUTTING  METALS 


permanently  attached  to  a  regulator.  The  regulator  is  in 
communication  with  two  cylinders  A  and  B,  one  of  which  can 
be  shut  off  when  the  other  is  in  use.  Thus,  if  the  valve  of 


FIG.  15.— Draeger's  High-Pressure  Eefill  Pump. 

cylinder  A  and  the  pipe  valve  a  are  open  whilst  the  valve  of 
cylinder  B  and  the  pipe  valve  b  are  closed,  oxygen  flows  from 
cylinder  A  through  the  regulator  until  it  begins  to  empty. 
The  valves  of  cylinder  A  are  then  closed  and  those  of  cylinder 
B  opened.  Oxygen  will  then  flow  from  cylinder  B  whilst  the 


WELDING  49 

empty  A  cylinder  can  be  removed  and  replaced  by  a  full  one. 
Thus  it  will  be  readily  seen  that  a  continuous  supply  of 
oxygen  can  be  maintained  to  the  blowpipes  by  the  employ- 
ment of  this  connector,  and  for  permanent  work  regulators 
with  this  connector  will  be  found  more  convenient  and  reliable 
than  those  fitted  with  pressure  gauges.  A  separate  pressure 
gauge  (Fig.  10,  p.  44) — preferably  of  the  larger  diameter — 
should  be  in  the  possession  of  all  constant  users  of  cylinders 
to  enable  them  to  check  the  contents  of  cylinders  when  they 
arrive  from  the  compressing  factory. 

Draeger's  High-Pressure  Refilling  Pump,  as  illustrated  in 
Pig.  15,  enables  trade  cylinders  to  be  filled,  in  various  stages, 
from  storage  vessels  containing  the  gas  under  different  high 
pressures. 

The  three  storage  vessels,  1,  2,  3,  containing  the  gas  at 
pressures  of,  say,  1,  40,  and  80  atmospheres,  are  connected  by 
means  of  strong  piping  to  the  pump  valves  at  K.  The  mano- 
meter M1  shows  the  pressure  in  the  respective  storage  vessels 
from  which  the  gas  is  to  be  supplied,  and  the  manometer  M2 
the  pressure  obtained  in  the  trade-cylinder.  S  represents  the 
closing  valve  of  the  pump  when  the  trade-cylinders  are  being 
exchanged,  and  T  is  the  closing  valve  of  the  cylinders. 

PUEIFYING  MATEEIAL. 

There  are  various  purifying  substances  described  by  Messrs. 
Leeds  and  Butterjield,  analytical  chemists,  as  follows : — 

There  are  three  principal  chemical  reagents  in  regular  use. 
These  are  chromic  acid,  cuprous  chloride  (sub-  or  proto-chloride 
of  copper)  and  bleaching  powder. 

Chromic  acid  is  employed  in  the  form  of  a  solution  acidified 
with  acetic  or  hydrochloric  acid,  which,  in  order  to  obtain  the 
advantages  attendant  upon  the  use  of  a  solid  purifying  material, 
is  absorbed  in  the  highly  porous  and  inert  silica  or  kieselguhr. 

w.  E 


50  WELDING  AND   CUTTING  METALS 

This  substance  was  first  recommended  by  Ullmann,  and  is 
termed  commercially  Heratol  As  sold  it  contains  about 
136  grammes  of  chromic  acid  per  kilogramme. 

Cuprous  chloride  is  used  as  a  solution  in  strong  hydrochloric 
acid,  mixed  with  ferric  chloride,  and  similarly  absorbed  in 
kieselguhr.  From  the  name  of  its  proposer  this  composition 
is  called  Frankoline. 

As  a  special  acetylene  purifier  bleaching  powder  exists  in 
at  least  two  chief  modifications.  In  one,  known  as  Acogine, 
it  is  mixed  with  15  per  cent,  of  lead  chromate,  and  sometimes 
with  about  the  same  quantity  of  barium  sulphate,  the  function 
of  the  latter  being  simply  that  of  a  diluent,  while  to  the  lead 
chromate  is  ascribed  by  its  inventor,  Wolff,  the  power  of 
retaining  any  chlorine  that  may  be  set  free  from  the  bleaching 
powder  by  the  reduction  of  the  chromic  acid. 

Puratylene,  as  the  second  modification  of  bleaching  powder, 
contains  calcium  chloride  and  quick  or  slaked  lime. 

It  will  be  observed  that  both  Heratol  and  Frankoline  are 
powerfully  acid,  whence  it  follows  they  are  capable  of  extract- 
ing any  ammonia  that  may  enter  the  purifier,  but  for  the  same 
reason  they  are  liable  to  act  corrosively  upon  any  metallic 
vessel  in  which  they  are  placed,  and  they  therefore  require  to 
be  kept  in  earthenware  or  enamelled  receivers.  But  since 
they  are  not  liquid  the  casing  of  the  purifier  is  immaterial. 

Puratylene  also  removes  ammonia  by  virtue  of  the  calcium 
chloride  in  it. 

Acogine  would  probably  pass  the  ammonia,  but  this  is  no 
objection,  as  the  latter  can  be  extracted  by  a  preliminary 
washing  in  water. 

Of  all  these  materials  Heratol  is  the  most  complete  purifier 
of  acetylene,  removing  phosphorus  and  sulphur  most  rapidly 
and  thoroughly,  and  not  appreciably  diminishing  in  speed  or 
efficiency  until  its  chromic  acid  is  practically  quite  used  up. 


ACETYLENE  WELDING  51 

On  the  other  hand,  Heratol  does  act  upon  pure  acetylene  to 
some  extent,  so  that  purifiers  containing  it  should  be  small 
in  size  and  frequently  exchanged. 

Frankoline  is  very  efficacious  as  regards  the  phosphorus, 
but  it  does  not  wholly  extract  the  sulphur.  It  does  not  attack 
acetylene  itself. 

Acogine  and  Puratylene,  both  being  bleaching  powders  more 
or  less,  are  alike  in  removing  phosphorus  to  a  satisfactory 
degree,  but  they  leave  some  sulphur  behind.  Acogine 
evidently  attacks  acetylene  to  a  slight  extent. 

Although  some  of  these  materials  attack  acetylene  slightly 
and  some  leave  sulphur  in  the  purified  gas,  they  may  be  all 
considered  reasonably  efficient  from  the  practical  point  of 
view,  for  the  loss  of  true  acetylene  is  too  small  to  be  noticeable 
and  the  quantity  of  sulphur  not  extracted  too  trifling  to  be 
harmful  or  inconvenient. 

For  employment  in  acetylene  installations  a  solid  purifying 
material  is  generally  preferable  to  a  liquid  one. 

Acogine  and  Puratylene,  although  they  may  bo  excellent  for 
lighting  installations,  are,  however,  unsuitable  for  a  welding 
plant  by  reason  of  the  severe  suction  of  the  acetylene  by 
means  of  the  oxygen,  which  may  cause  small  particles  of  lime 
to  be  drawn  into  the  burner. 

For  practical  purposes  about  1  kilogramme  of  purifying 
material  is  sufficient  for  15  to  20  cubic  metres  of  gas,  i.e.,  for 
about  50  kilogrammes  of  carbide. 


ACETYLENE  GENERATORS  FOR  WELDING. 
A.  Automatic  Low-pressure  Oxy -acetylene  Welding  Plant. 

A   low-pressure  welding  plant  consists   of     an   automatic 
or  a  non-automatic  acetylene  generator,  oxygen  cylinders  with 

E  2 


52  WELDING  AND   CUTTING  METALS 

regulators,  one  hydraulic  back-pressure  valve,  rubber  tubing 
for  oxygen,  rubber  tubing  for  acetylene,  spectacles,  cylinder 
key,  and  one  or  more  low-pressure  blowpipes.  The  ordinary 
sizes  of  automatic  acetylene  plants  have  a  container  for  15, 
30  and  60  Ibs.  of  carbide,  representing  a  supply  of  respectively 
15,  80  and  60  cubic  feet  of  gas. 

B.  Non-automatic  Low-pressure  Acetylene  Plant. 

This  consists  of  one  or  more  cast-iron  generators,  hydraulic 
main  and  washer,  counter  weighted  gasholder  of  suitable  size, 
and  purifier. 

The  generation  of  acetylene  by  merely  bringing  calcium 
carbide  and  water  into  mutual  contact  within  a  suitable  and 
closed  vessel,  and  the  great  facilities  offered  to  consumers  to 
obtain  the  carbide  in  a  condition  ready  for  use  and  decomposi- 
tion, is,  at  least  from  a  theoretical  point  of  view,  characterised 
by  extreme  simplicity. 

When,  however,  the  question  comes  to  select  an  apparatus 
for  welding  purposes  great  difficulties  appear  at  once.  The 
generator  should  be  of  the  best  make  and  principally  of  the 
right  type,  able  to  produce  the  gas  in  sufficient  quantity  and 
of  the  high  degree  of  purity  which  is  absolutely  essential  in 
producing  a  perfect  weld.  Moreover,  it  must  not  be  forgotten 
that  every  maker  does  not  possess  that  technical  knowledge 
which  is  required  to  give  proper  advice,  so  often  the  case  in  a 
new  industry,  although  it  must  freely  be  admitted  that  there 
are  no  generators  made  by  responsible  firms  at  the  present 
time,  which  are  not  safe ;  from  this,  however,  it  must  not  be 
deduced  that  every  type  of  generators  is  suitable  for  welding 
purposes. 

The  relative  advantages  of  automatic  and  non-automatic 
apparatus,  irrespective  of  type,  from  the  consumer's  point  of 
view,  may  be  stated  to  be  as  follows  : — 


ACETYLENE  WELDING  53 

The  fundamental  idea  underlying  the  employment  of  a  non- 
automatic  generator  is  that  the  whole  of  the  calcium  carbide 
put  into  the  apparatus  shall  be  decomposed  into  acetylene  as 
soon  after  the  charge  is  inserted  as  is  natural  in  the  circum- 
stances ;  so  that  after  a  very  brief  interval  of  time  the  gene- 
rating chambers  shall  contain  nothing  but  spent  lime  and  water, 
and  the  gasometer  be  as  full  of  gas  as  is  ever  desirable. 

In  an  automatic  apparatus  the  fundamental  idea  is  that  the 
generating  chamber,  or  one  at  least  of  several  generating 
chambers,  shall  always  contain  a  considerable  quantity  of 
undecomposed  carbide,  and  some  receptacle  always  containing 
a  store  of  water  ready  to  attack  that  carbide,  so  that  when- 
ever a  demand  for  gas  shall  arise  everything  may  be  ready  to 
meet  it. 

Inasmuch  as  acetylene  is  an  inflammable  gas,  it  possesses 
all  the  properties  characteristic  of  inflammable  gases  in 
general ;  one  of  which  is  that  it  is  always  liable  to  take 
fire  in  presence  of  a  spark  or  naked  light,  and  another  of 
which  is  that  it  is  always  liable  to  become  highly  explosive  in 
presence  of  a  naked  light  or  spark  if,  accidentally  or  otherwise, 
it  becomes  mixed  with  more  than  a  certain  proportion  of  air. 
On  the  contrary,  in  the  complete  absence  of  liquid  or  vaporised 
water,  calcium  carbide  is  almost  as  inert  a  body  as  it  is  possible 
to  imagine,  for  it  will  not  take  fire,  and  cannot  in  any  circum- 
stances be  made  to  explode.  Hence  it  may  be  urged  that  a 
non-automatic  generator,  with  its  gasometer  always  contain- 
ing a  large  volume  of  the  actually  inflammable  and  potentially 
explosive  acetylene,  must  invariably  be  more  dangerous  than 
an  automatic  apparatus,  which  has  less  or  practically  no  ready- 
made  gas  in  it,  and  which  simply  contains  water  in  one 
chamber  and  unaltered  calcium  carbide  in  another.  But 
when  the  generating  vessels  and  the  gasometer  of  a  non- 
automatic  apparatus  are  properly  designed,  the  gas  in  the 


•54  WELDING  AND   CUTTING  METALS 

latter  is  acetylene  practically  free  from  air,  and  therefore, 
while  heing  inflammable  it  is  devoid  of  explosive  properties, 
always  assuming  that  the  temperature  of  the  gas  is  below  280°  C. 
and  that  the  pressure  under  which  the  gas  is  stored  remains 
less  than  two  atmospheres. 

It  may  be  well  to  remember  that  not  only  must  calcium 
carbide  and  water  be  kept  out  of  premature  contact,  but  that 
moisture,  or  vapour  of  water,  must  not  be  allowed  to  reach 
the  carbide;  or  alternatively,  that,  if  water  vapour  reaches 
the  carbide  too  soon,  the  undesiied  reaction  shall  not  deter- 
mine overheating,  and  the  liberated  gas  be  not  wasted  or 
permitted  to  become  a  source  of  danger. 

The  evolution  of  the  gas  must  be  slow  and  regulated  so 
that  an  apparatus,  for  instance,  with  a  storage  of  17  kilo- 
grammes of  carbide,  representing  a  capacity  of  17  X  300  = 
5,100  litres  of  gas,  can  be  used  during  ten  hours  with  a 
consumption  of  500  litres  of  gas  per  hour  ;  a  similar  apparatus 
with  a  storage  of  50  kilogrammes  of  carbide  with  a  consump- 
tion of  1,500  litres  of  gas  per  hour,  and  an  apparatus  with 
100  kilogrammes  storage  of  carbide  with  a  consumption  of 
3,000  litres  of  gas  per  hour. 

For  a  consumption  larger  than  3,000  litres  of  gas  per  hour, 
the  non-automatic  apparatus  must  be  employed. 

It  is  difficult,  and  it  may  not  even  be  advisable,  to  give  a 
direct  answer  to  the  question  as  to  which  is  the  best  type  of 
acetylene  generators.  Experience  has,  however,  proved,  so  far 
as  welding  is  concerned,  that  the  apparatus  in  which  granu- 
lated carbide  is  used,  the  generated  gas  is  of  too  impure  a 
quality  to  be  used  for  welding,  producing,  as  it  will,  a  brittle 
weld. 

The  type  in  which  the  water  is  allowed  to  drip  on  to  the 
carbide  should  on  no  conditions  be  used,  as  being  the  most 
unsuitable  of  all. 


ACETYLENE  WELDING  55 

The  carbide-to-water  generator,  by  reason  of  its  many 
advantages  from  a  theoretical  point  of  view,  has,  also  for 
practical  purposes,  proved  to  be  the  best,  producing,  as  it 
will,  a  perfect  weld. 

When  deciding  the  size  of  the  apparatus  to  be  selected,  it 
should  be  borne  in  mind  that  as  little  as,  for  instance,  a 
dynamo  can  produce  an  unlimited  quantity  of  energy  without 
causing  harm  to  the  machine,  as  little  can  an  acetylene 
apparatus  generate  an  unlimited  quantity  of  gas.  The 
quicker  the  evolution,  the  more  impure  is  the  gas  and  the 
more  unsatisfactory  will  the  weld  be. 

A  preliminary  estimate  should  therefore  be  carefully  made 
of  the  quantity  of  gas  that  would  probably  be  required. 
Assuming,  for  instance,  that  100  metres  of  plate,  with  a 
thickness  of  8  m.m.  shall  be  welded  per  day,  four  welders 
would  be  required,  each  with  a  blowpipe  consuming  650  litres 
of  gas  per  hour,  making  for  the  four  blowpipes  2,700  litres  of 
gas  per  hour.  It  would  be  necessary,  therefore,  to  provide  an 
apparatus  capable  of  generating  3,000  litres  of  acetylene  per  hour. 
The  weight  of  calcium  carbide  required  to  produce  a  certain 
quantity  of  gas  may  be  estimated  from  the  formula  :  Carbide 

in  kilogrammes  =  consumption  per  hour  in  litres   X   10  Qr 
production  of  gas  per  kilogramme  carbide 

-  =  100  kilogrammes  of  carbide  would  be  required. 

oUU 

As  each  kilogramme  of  carbide  requires  at  least  7'5  litres  of 
water,  the  gas  generator  should  be  provided  with  a  space  large 
enough  to  hold  at  least  750  litres  of  water. 

It  is  indifferent,  however,  how  the  generated  gas  is  consumed, 
if  by  ten  welders,  each  with  150  litres,  or  by  one  welder  with 
1,200,  and  two  welders  with  150  litres  each  per  hour,  but  the 
consumption  per  hour  must  be  provided  by  acetylene  generated 
in  a  normal  manner. 


56  WELDING  AND  CUTTING  METALS 

The  decomposition  of  the  carbide  in  the  water  requires 
ample  time.  It  may,  however,  be  possible  to  provide 
additional  quantities  of  carbide,  but  then  the  temperature 
would  also  increase  accordingly,  even  up  to  675°  C.  In  addi- 
tion to  this  the  acetylene  requires  considerable  time  to  cool, 
and  only  a  certain  quantity  can  pass  through  the  chemical 
purifier  to  enable  a  normal  and  effective  work  to  be  done. 
The  gas  produced  at  too  high  a  temperature  would  not  only 
increase  the  danger  of  explosion  but  the  products  of  condensa- 
tion would  tend  to  make  the  gas  impure.  The  higher  the 
temperature  the  greater  is  the  quantity  of  sulphur  and  organic 
sulphur  compounds.  The  more  rapid  the  generation,  the 
greater  is  the  impurity  of  the  gas,  and  the  more  unsatisfactory 
will  the  weld  be. 

Some  automatic  apparatus  are  being  offered  in  the  foreign 
market  for  a  production  of  4,000  and  even  12,000  litres  of 
acetylene  per  hour ;  they  contain,  however,  only  8  and 
25  kilogrammes  of  carbide,  and  should  therefore  be  used 
for  a  consumption  of  250  and  750  litres  per  hour  respec- 
tively. 

Another  apparatus  with  an  indicated  generating  power  of 
25,000  litres  of  gas  per  hour  is  likewise  being  offered.  This 
apparatus  should  therefore  have  a  storage  capacity  for  800 
kilogrammes  of  carbide  and  6,000  litres  of  water.  In  reality 
it  contains  40  kilogrammes  of  carbide. 

The  effective  size  and  not  the  indicated  production  should 
constitute  the  regulator  of  price  of  the  apparatus. 

It  is  easily  understood  the  harm  that  may  be  done  by 
offering  acetylene  generators  of  too  small  a  size  in  order  to 
facilitate  a  sale.  The  inevitable  results  will  appear  in  increased 
danger  of  explosion  and  an  imperfect  weld,  followed  by  sus- 
picion and  consequent  delay  in  the  development  of  this  new, 
but  so  important,  industry. 


ACETYLENE  WELDING 


57 


INSULATOR. 

The  insulation  of  buildings,  more  particularly  those  used 
for  acetylene  generators,  is  of  vital  importance  from  a  point 
of  safety.  Perfect  insulation  is  almost  impossible,  but  a 
good  insulation  can  be  had. 

Messrs.  Lamb  and  Wilson,  of  Cambridge  University,  in  a 
paper  communicated  to  the  Koyal  Society  by  Prof.  Ewing, 
F.R.S.,  in  1899,  have  published  the  results  of  tests  made  by 
them  as  follows  :— 


Insulator. 

Average 
cubic  cms. 
per  day 
of  water 

Weight 
of 
insulator. 
Lbs. 

Comparative 
amount  of 
heat  lost  per 
insulator 
(irrespective 

Compara- 
tive 
weight. 

Resultant 
theoretical 
number. 

of  weight). 

Silicate  cotton  l  . 

789 

75 

0-860 

1-000 

•860 

Cartvale  flake  charcoal 

916 

75 

1-000 

1-000 

1-000 

Felt  a.         .         . 

980 

57 

•070 

•76 

•813 

Fossil  meal         . 

1,044 

100 

•138 

1-33 

1-513 

Plain  cork  slabs  . 

1,168 

106 

•273 

1-413 

1-798 

Tarred  cork  slabs 

1,217 

128 

•327 

1-7 

2-255 

Lump  charcoal  3  . 

1,326 

139 

•446 

1-853 

2-679 

Ashes  .        .... 

1,943 

273 

2-110 

3-64 

7-716 

The  Cartvale  flake  charcoal  is  thus  superior  in  its  insulating 
value  as  compared  with  the  other  materials,  while,  owing  to 
its  lightness,  much  less  weight  of  it  is  required  to  fill  a  given 
space,  and  yet  give  better  insulation. 

It  may  be  remembered  that  the  amount  of  heat  to  be  over- 
come is  not  to  be  measured  by  the  cubical  contents  of  the 
insulating  room,  but  by  the  amount  of  square  or  wall  surface 
exposed  to  the  heated  exterior. 

1  Silicate  Cotton  has  been  found  practically  to  be  out  of  the  question, 
as  it  breaks  down  easily,  leaving  open  spaces,  or  falls  down  to  powder. 

2  Felt  absorbs  damp  very  quickly,  and,  owing  to  its  composition,  draws- 
up  water  by  capillary  attraction,  thus  spoiling  it  as  a  non-conductor  and 
rotting  it ;  in  addition,  it  is  apt  to  breed  vermin. 

3  The  lump  charcoal  was  first  broken  into  pieces  about  half -inch  cube. 


oS  WELDING  AND   CUTTING  METALS 

C.  High-pressure  Oxy -acetylene  Welding  Plant. 

In  this  type  of  welding  plant  the  acetylene  is  used  in  a 
compressed  state,  similar  to  that  of  the  oxygen. 

Like  all  other  gases,  acetylene  is  capable  of  compression  and 
liquefaction,  and  when  used  in  this  form  is  called  "  dissolved 
acetylene,"  and  known  abroad  under  the  name  of  "  acetylene- 
dissous."  It  is  produced  as  follows  : — 

The  acetylene,  generated  in  the  usual  way,  is  thoroughly 
washed  and  subjected  to  no  less  than  five  different  processes 
of  purification,  and  dried.  It  is  then  compressed  and  passed 
into  the  ordinary  steel  cylinders  for  storage.  The  compres- 
sion is  carried  out  by  a  double-acting  pump,  which  compresses 
it  in  two  stages,  as  the  process  is  accompanied  by  an  evolution 
•of  much  heat,  which  might  cause  the  gas  to  explode  during 
the  operation ;  but  since  the  pump  is  fitted  with  two  cylinders, 
the  acetylene  can  be  cooled  after  the  first  compression. 

The  cylinders,  of  any  size,  are  filled  with  a  porous  solid 
material  in  the  form  of  a  charcoal  cement,  and  charged  to 
about  43  per  cent,  of  their  capacity  with  acetone,  thus  leaving 
37  per  cent,  of  the  space  for  expansion  which  takes  place, 
making  an  explosion  in  the  cylinder  an  impossibility.  Acetone 
is  a  liquid,  which  has  the  peculiar  property  of  absorbing  twenty- 
five  times  its  own  volume  of  acetylene  at  atmospheric  pressure 
and  15°  C.,  and  will  continue  doing  this  for  every  atmosphere 
of  pressure  that  is  applied  to  the  gas.  The  quantity  of 
acetone  in  the  cylinders  is  so  regulated  that  they  contain 
ten  times  their  own  volume  of  acetylene  for  every  atmosphere 
of  pressure.  The  gas  in  the  cylinders  sent  out  by  the  com- 
pany is  compressed  to  ten  atmospheres,  so  that  they  contain 
-one  hundred  times  their  own  volume  of  acetylene. 

The  safety  of  the  system  has  been  demonstrated  in  the 
fullest  possible  manner  to  the  Home  Office,  in  consequence  of 


ACETYLENE  WELDING 


59 


which  the  Secretary  of  State  for  the  Home  Department,  in 
April,  1901,  issued  an  order  recognising  the  safety  of  dissolved 
acetylene,  and  authorising  its  use  according  to  the  process 
adopted  by  the  Acetylene  Illuminating  Company  on  condition 
that  (1)  the  porous  material  used  is  to  be  exactly  similar  to 
the  sample  deposited  with  the  Home  Office,  (2)  all  cylinders 
are  to  be  tested  according  to  certain  rules  laid  down,  (3)  certain 
technical  details  in  the  manufacture  of  the  gas  and  charging 
of  the  cylinders  be  carefully  observed,  (4)  that  every  facility 
be  given  to  the  Government  inspectors  to  inspect  the  com- 
pany's plant  and  method  of  working,  and  (5)  every  cylinder 
or  container  to  bear  the  name  of  the  Acetylene  Illuminating 
Company,  Limited,  and  be  marked  "  Acetylene  compressed 
into  porous  substance  exempted  by  order  of  Secretary  of 
State,  dated  10th  April,  1901." 

For  autogenous  welding  in  conjunction  with  oxygen  dis- 
solved acetylene  offers  many  advantages,  particularly  in 
places  inaccessible  to  other  welding  plants  or  systems,  such, 
for  instance,  as  the  hold  of  a  ship. 

The  gas  being  chemically  pure  is  always  cool  and  dry,  and 
at  a  steady  pressure  most  suitable  to  ensure  maximum  of 
efficiency.  The  consumption  of  the  gas  is  shown  by  the 
gauge,  so  that  the  quantity  remaining  in  the  cylinder  is 
known  at  a  glance. 

CYLINDERS  FOR  ACETYLENE-DISSOUS. 


Cubic  contents  in 
feet. 

External  diameter  in 
inches. 

Length  over  all  in 
inches. 

Weight  in  Ibs. 
approximately. 

60 

6-25 

41-5 

64 

100 

8-25 

40'0 

95 

175 

10-5 

47-0 

180 

200 

10*5 

52-5 

195 

200 

14-25 

28-5 

165 

60  WELDING  AND  CUTTING  METALS 

High-pressure  oxy-acetylene  welding  plant  consists  of  the 
acetylene  cylinder ;  the  oxygen  cylinder  ;  the  regulator  and 
safety  device,  fitted  with  two  pressure  gauges  for  the  acety- 
lene cylinder ;  and  similar  ones  for  the  oxygen  cylinder ;  one 
or  more  high-pressure  blowpipes ;  two  lengths  of  rubber 
tubing;  spectacles;  and  cylinder  key. 

When  working  high-pressure  plant,  first  examine  cylinder 
valve  to  see  if  same  is  clean.  The  governor  can  then  be 
screwed  into  the  valve  (this  is  a  left-hand  thread),  making 
sure  the  joint  is  sound.  The  same  thing  must  be  done  with 
the  oxygen  cylinder.  In  this  case  the  thread  of  the  governor 
is  right  hand. 

The  regulators  for  the  acetylene  cylinders  are  painted  red 
and  have  left-hand  connections  to  fit  the  valve  in  the  acetylene 
cylinders ;  the  regulators  for  the  oxygen  cylinders  are  painted 
black  and  have  right-hand  connections.  This  is  done  so  as 
to  make  it  impossible  for  the  wrong  regulators  to  be  used 
with  either  gas,  otherwise  they  are  identical.  The  pressure 
can  be  adjusted  by  unscrewing  the  screw  K  (Fig.  8,  p.  43) 
for  low  pressure,  or  by  screwing  down  K  for  high  pressure. 
The  indicator  M  indicates  the  pressure  of  delivery  as  set  by  K. 
The  maximum  pressure  at  which  the  regulator  will  work  is 
marked  by  a  red  line  on  the  indicator  M,  and  if  this  pressure 
is  exceeded  (by  screwing  K  too  heavily)  a  safety-valve  S  will 
open  and  relieve  the  excess  pressure.  The  tap  H  for  con- 
trolling the  supply  is  a  convenience  which  the  safety-valve  S 
renders  possible.  N  is  the  delivery  nozzle,  and  F  is  a  gauge 
for  registering  pressure  of  gas  in  cylinder. 

Then  connect  the  outlet  of  the  acetylene  governor,  by 
means  of  rubber  tubing,  to  the  nozzle  on  the  blowpipe, 
stamped  A,  and  the  oxygen  governor  to  the  nozzle  on  blow- 
pipe marked  0.  Care  should  be  taken  to  bind  the  rubber  at 
all  joints  with  wire. 


ALUMINIUM  WELDING  61 

Then  see  that  the  milled  head  screw  on  outlet  of  each 
governor  is  open,  and  that  tap  K  on  top  of  each  governor 
is  free  from  the  governor  springs  (this  is  so  when  tap  R  is 
nearly  out  of  the  socket).  Then  turn  on  the  gas  at  both 
cylinder  valves ;  no  gas  will  pass  to  the  burners  if  the  tap  R 
on  the  regulators  is  free.  Screw  down  the  tap  R  on  top 
of  the  acetylene  governor  until  pressure  on  outlet  gauge 
shows  3  to  3 \  Ibs. ;  light  the  burner,  then  screw  down  tap  R 
on  the  oxygen  governor  until  the  necessary  white  tip  on  the 
burner  is  obtained,  gradually  increase  the  pressure  on  the 
acetylene  until  it  reaches  5|  Ibs.  Do  not  do  this  in  one  step, 
but  work  the  two  governors  alternately. 

WELDING  OF  ALUMINIUM. 

The  welding  of  aluminium  has  met  with  great  difficulties  by 
reason  of  the  great  ability  of  oxidation  of  the  material.  The 
moment  it  has  been  prepared  and  cleansed,  the  aluminium  is 
at  once  covered  with  aluminium  oxide,  which  prevents  the 
pieces  fusing  together.  By  using  a  flux,  however,  the  oxida- 
tion skin  is  dissolved,  and  a  dross  is  simultaneously  formed 
which  enables  the  metal  to  flow  and  make  a  perfect  weld. 
The  weld  remains  indifferent  in  solutions  of  common  salt 
and  soda,  and  is  in  every  respect  comparable  with  rolled 
aluminium. 

There  are  various  systems  for  soldering  aluminium,  and 
for  welding ;  for  instance,  those  of  M.  D.  Schocp  and  W.  C. 
Heraeus.  The  former  is  described  as  follows : — 

The  numerous  alloys  of  the  aluminium-copper-tin  or  tin- 
bismuth-copper  type,  which  have  been  used  for  soldering 
aluminium  at  moderately  low  temperature,  are  all  open  to 
the  same  objection,  that  the  soldered  joint  slowly  loses  its 
cohesion,  i.e.,  mechanical  strength.  This  is  due  to  the  fact 


62 


WELDING  AND  CUTTING  METALS 


PIG.  16. 


ALUMINIUM  WELDING  63 

that  aluminium,  particularly  in  the  presence  of  water,  com- 
pares unfavourably  with  other  metals  on  account  of  the 
"  electrolytic  local  action,"  the  aluminium  becoming  slowly 
decomposed. 

Apart  from  the  admixture  of  the  deoxydising  substance, 
which  plays  the  same  part  as  borax  does  in  soldering,  the 
welding  of  aluminium  is  similar  to  lead-burning.  The  weld- 
ing requires  no  special  preparations  nor  any  plant  beyond  the 
equipment  of  tools  necessary  for  the  efficient  handling  of  the 
aluminium. 

The  difficulty  to  be  overcome  was,  therefore,  to  find  means 
whereby  welding  of  aluminium  could  be  made  without  the 
addition  of  another  metal,  eliminating  thereby  electrolytic 
difficulties,  and  ensuring  the  same  physical  and  chemical 
properties  of  the  weld  as  those  of  the  bar  or  plate  to  be 
welded. 

The  welding  of  aluminium  has  been  successfully  accom- 
plished by  the  Schoop's  process.  The  Government  Institution, 
Le  Laboratoire  du  Conservatoire  National  des  Arts  et  Metiers 
a  Paris,  has  made  some  microphotographic  tests,  reproduc- 
tions of  which  are  given  in  Fig.  17  of  the  autogenously 
welded  aluminium,  and  Fig.  18  of  the  unwelded  aluminium. 

Again,  it  is  well  known  that  aluminium,  like  lead,  is 
attacked  by  the  atmosphere,  and  becomes  coated  with  a 
layer  of  oxide,  but  whereas  in  the  case  of  lead  this  oxidation- 
product  can  easily  be  removed,  the  coating  on  aluminium  has 
hitherto  resisted  all  practicable  modes  of  removal.  By  means 
of  a  flux,  however,  the  very  tough  layer  of  oxide  is  imme- 
diately removed  under  the  blowpipe  flame,  and  the  surfaces 
thus  cleaned  and  fused  are  readily  united  and  produce  a 
direct  union  of  aluminium  with  aluminium  without  in  any 
way  impairing  the  original  metal. 

The   principal   point   is    that    the    blowpipe   flame   be   of 


64 


WELDING  AND   CUTTING  METALS 


sufficiently  high  temperature  to  fuse  the  surface  of  the  alumi- 
nium.    For  aluminium  sheeting  1  mm.  thick  coal-gas  and 

FIG.  17. 


FIG.  18. 


oxygen   would   suffice,  whilst  for   stout   aluminium  sheeting 
acetylene  and  oxygen  would  be  preferable. 


ALUMINIUM  WELDING 


65 


Constants  of  Aluminium. 

Atomic  weight 27*0 

Specific  gravity  (cast) 2-6  at  4  per  cent. 

,,  „        (rolled  or  hammered)          .         .         .       2'67      ,, 

Melting  point 650°  0. 

Tensile  and  compressive  strength  of  cast  aluminium  ,     10  at  12  kilos 

per  sq.  mm. 

rolled       .,  .     25  at  27  kilos 

per  sq.  mm. 
Electric  conductivity  (copper  =  100)  .         .         .60 


Tests  of  Tensile  Strength. 

By   the   Swiss    Federal    Testing    Institute,  attached   to   the 
Polytechnicum  in  Zurich  : — 

w  =  welded,     u  =  unwelded.     The  spots  where  the  pieces  are  welded 
are  marked  by  a  black  line. 


w.  6  mm. 
u.  6  mm. 


w.  1*8  mm. 
u.  1*8  mm. 


w.  1'8  mm. 
u.  1'8  mm. 


w.  1'8  mm. 
u.  1-8  mm. 


Welded  edge  to 
edge.  Rupture 
outside  the 
welded  joint. 


The  hammered 
welded  joint  is 
parallel  with 
last  rolling. 


The  hammered 
welded  joint 
runs  crossivise 
to  the  last  roll- 
ing. 


The  rupture  at 
the  welded  un- 
hammered 
joint. 


FIG.  19. — Aluminium. 


66 


WELDING  AND   CUTTING  METALS 


w.  2  mm. 
u.  2  nim. 


w.  2  mm. 
u.  2  mm. 


w.  2  mm. 
u.  2  mm. 


Welded  twice. 
Rupture  out- 
side the  two 
ham  mere  d 
welded  joints. 


Rupture  outside 
welded  and 
hammere  d 
joint. 


Rupture  outside 
welded  unham- 
mered  joint. 


FIG.  20. — Magnalium. 


w.  1-5  mm. 
u.  1-5  mni. 


Rupture  outside 
welded  and 
hammered 
joint. 


FIG.  21. — Wolfram  Aluminium. 

The  results  of  the  above  tests  show  that  the  welding  does 
not  weaken  the  strength  of  the  metal ;  on  the  contrary,  the 
welded  joints  are  showing  even  greater  strength  than  the 
un welded  places,  provided  that  they  are  hammered  after 
welding.  Local  contraction  and  rupture  always"  occurred 
outside  the  joint,  with  the  exception  of  test  4,  where  the 
rupture  occurred  at  an  unhammered  joint. 

In  test  4  the  welded  seam  lies  parallel  with  the  direction  of 
the  last  rolling.  In  test  5  it  runs  crosswise,  for  which  reason 
the  tensile  strength  is  greater  in  4,  viz.,  9'4  kg.  per  sq.  mm., 
as  against  9*1  kg. 

Tests  5  to  7  refer  to  magnalium  testing,  the  pieces  being  of 
the  same  thickness,  showing  increased  breaking  strain  and 
resisting  power ;  the  former  amounts  to  147  per  cent,  of  the 


ALUMINO-THEEMIC  WELDING  67 

unwelded  pieces  and  the  latter  to  104*6  per  cent.  On  the 
other  hand  the  percentage  elongation  (absolute  value  20*3  per 
cent.)  is  reduced  by  two-thirds,  viz.,  to  30'8  per  cent,  of  the 
unwelded  sheet. 

In  test  7  the  unhammered  piece  parted  outside  the  welded 
joint,  contrary  to  the  respective  test  for  aluminium.  This  is 
only  owing  to  the  different  mode  of  treatment  of  the  aluminium 
and  the  magnalium.  The  former  was  suddenly  cooled  by 
being  plunged  into  cold  water  whilst  red  hot,  the  latter  being 
left  to  cool  gradually. 

The  tests  were  concluded  by  two  Wolfram  aluminium 
samples  1*5  mm.  thick.  This  alloy  showed  the  greatest 
tensile  strength,  viz.,  32'6  kg.  per  sq.  mm.,  or  nearly  twice 
that  of  a  6  mm.  aluminium  sheet  16'7  kg. 

The  breaking  strain  is  the  same  for  welded  and  un- 
welded aluminium,  the  resistance  somewhat  lower,  whilst 
the  percentage  elongation  again  is  higher  than  the  unalloyed 
aluminium. 

THE  ALUMINO-THERMIC  PROCESS. 

The  two  elements  of  most  frequent  occurrence  are  oxygen 
and  aluminium.  By  exposing  them  in  a  suitable  manner  to  a 
chemical  combination,  a  temperature  is  created  which  is  about 
equal  to  that  of  the  electric  arc.  On  this  discovery  is  based 
the  Alumino-thermic  process. 

The  compound  "  Thermit  "  consists  of  a  mixture  of  finely 
ground  aluminium  and  an  oxide  of  a  metal ;  when  this  is 
ignited,  the  aluminium  oxidises,  that  is,  absorbs  oxygen  so 
rapidly  that  an  intense  heat  is  the  result.  In  the  process  of 
oxidation,  the  aluminium  takes  the  oxygen  from  the  metallic 
oxide,  leaving  a  pure  metal  and  oxide  of  aluminium,  both  in 
superheated  form. 

F  2 


68  WELDING  AND   CUTTING  METALS 

The  mixture  or  compound  is  placed  in  crucibles  which  are 
not  in  contact  with  any  external  source  of  heat,  and  the  com- 
bustion, once  started,  embraces  the  whole  mass  in  a  very  short 
time. 

In  the  crucible  after  the  reaction  there  are  two  layers.  The 
bottom  one  is  pure  metal  of  equal  weight  to,  but  occupying 


FIG.  22.— Complete  Eail  Welding  Outfit. 

only  one -third  of  the  space  of  the  top  layer,  which  is  now  oxide 
of  aluminium,  so-called  corundum. 

The  crucibles  consist  of  a  sheet  iron  shell  lined  with  a 
special  mixture  of  magnesite  and  bituminous  cement ;  they 
are  of  simple  construction  and  will  stand  about  twenty 
reactions ;  the  wear  and  tear  therefore  amount  to  only  a 
few  pence  per  joint. 

"  Thermit "  is  not  explosive.  It  can  only  be  ignited  at  a 
temperature  of  about  2,000°  Fahr.,  which  in  practice  is 
obtained  by  means  of  a  special  ignition  powder  placed  in  a 
little  heap  on  the  top  of  the  compound  and  ignited  by  means 


ALUMINO-THEKMIC  WELDING 


69 


of  a   flaming   vesta.     The   temperature   generated   is   about 
5,400°  Fahr. 

A  simple  application  of  the  alumino-thermic  process  is  that 
for  welding  of  tramway  rails,  and  the  third  or  conductor  rails 
of  electric  railways,  obviating  the  use  of  bands  and  their 


FIG.  23.— Mould,  with  Tools. 


Outside  Model  of  Rail  and  Mould  Case.  O. 

Mould  Case  End.  P. 

Shovel.  Q. 

Inside  or  Check  Side  Model  of  Rail  and  R. 

Mould  Case.  S. 

Mould  Rammer.  T. 


Wooden  Mallet. 

Outside  Mould  filled  ready  for  use. 

Pricker. 

Moulders'  Tool. 

Inside  Mould  filled  ready  for  use. 

Hammer,  3Jlb. 


consequent  troubles.  Underground  systems  can  be  welded 
throughout  without  fear  of  trouble  from  expansion  or  contrac- 
tion, but  on  lines  where  the  rails  are  entirely  exposed  occasional 
expansion  joints  should  be  allowed  for. 

A  welding   plant  consists   of   a   crucible,   accessories,  and 


70  WELDING  AND   CUTTING  METALS 

mould  box,  the  whole  of  which  can  easily  be  carried  on  a 
hand  truck  (Fig.  22). 

A  mould  is  made  according  to  a  model  designed  specially 
for  each  separate  operation ;  for  instance,  in  the  welding  of 
rails,  a  mould  in  two  parts,  one  on  each  side  of  the  rail, 
firmly  encloses  and  exactly  fits  the  rail  (Fig.  23).  The  steel 
running  out  of  the  crucible  flows  round  the  web  and  foot  of 
the  rail,  and,  melting  them,  forms  one  mass  with  them.  The 
liquid  slag  which  follows  the  metal  is  diverted  to  the  top  of 
the  rail  and  brings  the  latter  to  welding  heat.  The  whole 
section  is  thus  heated  equally  and  the  rail  ends  will  not  buckle. 

The  welding  is  done  automatically  and  does  not  require  an 
expert  welder,  but  may  easily  be  carried  out  by  the  permanent 
staff  of  any  company. 

The  Paris  Metropolitan  Railway  made  some  experiments  on 
a  short  track,  with  the  result  that  after  one  year's  trial  1,200 
joints  were  welded  in  1904 ;  the  rails  are  104  Ibs.  per  yard. 
In  1906  a  further  1,800  joints  were  welded,  part  of  which  were 
on  exposed  track,  in  which  case  lengths  of  250  yards  were 
welded  together,  having  an  expansion  joint  between.  The 
results  obtained  having  proved  satisfactory,  the  directors 
decided  to  weld  the  whole  system,  some  10,000  joints,  in  a 
similar  manner. 

On  the  suburban  railway  from  Berlin  to  Grosslichterfelde, 
the  Allgem.  Elektr.  Ges.  of  Berlin,  have  welded  13J  miles 
of  track.  The  rails  on  this  track  are  exposed  ;  three  lengths 
of  45  ft.  rails  are  welded  together  and  connected  to  the  next 
by  an  expansion  joint. 

The  question  of  a  continuous  rail  on  exposed  railways  is  not 
yet  solved,  for  want  of  sufficient  tests.  That  it  is  practicable 
within  certain  limits,  and  that  it  is  desirable  to  have  greater 
lengths  of  exposed  track  welded  together,  is  admitted  by 
permanent  way  engineers.  In  any  case  exposed  rails  can 


ALUMINO-THEKMIC  WELDING  71 

undoubtedly  be  welded  without  any  risk  in  tunnels  and 
subways  where  differences  of  temperature  are  very  slight, 
and  contraction  and  expansion  therefore  only  minimal. 

The  matter  of  securing  a  proper  joint  for  fastening  together 
the  ends  of  rails  so  as  to  make  a  smooth  riding  track  without 
appreciable  jar  or  jolt  when  the  wheels  pass  a  joint  deserves, 
therefore,  great  consideration,  and  many  forms  of  such  joints 
have  been  suggested.  All  of  these  welded  joints  fasten  the 
ends  of  the  rails  together,  so  that  the  rail  is  practically  con- 
tinuous, just  as  if  there  were  no  joints,  so  far  as  the  running 
surface  of  the  rail  is  concerned. 

It  was  thought  at  one  time  that  a  continuous  rail  would  be 
an  impossibility  because  of  the  contraction  and  expansion  of 
the  rail  under  heat  and  cold,  which,  it  was  thought,  would  tend 
to  pull  the  rails  apart  in  cold  weather  and  to  cause  them  to 
bend  and  buckle  out  of  line  in  hot  weather.  Experience  has 
conclusively  shown,  however,  that  contraction  and  expansion 
need  not  be  taken  into  account  when  the  track  is  paved,  pro- 
vided it  is  well  constructed  and  long  lengths  of  rail  are  not 
left  exposed  to  the  rays  of  a  hot  sun  for  a  considerable  period. 
The  paving  tends  to  hold  the  track  in  line,  and  to  protect  it 
from  extremes  of  heat  and  cold.  The  reason  that  contraction 
and  expansion  do  not  work  havoc  on  track  with  welded  joints 
is  probably  that  the  rails  have  enough  elasticity  to  provide 
for  the  contraction  and  expansion  without  breaking. 

It  is  found  that  the  best  results  are  secured  by  welding  rail 
joints  during  cool  weather,  so  that  the  effect  of  contraction  in 
the  coldest  weather  will  be  minimum.  In  this  case,  of  course, 
there  might  be  considerable  expansion  of  the  track  in  the 
hottest  weather,  but  this  does  not  cause  bending  of  the  rails, 
whereas  occasionally,  if  the  track  is  welded  in  very  hot  weather, 
the  contraction  in  winter  will  cause  the  rail  to  break. 

The  following  tests,  carried  out  by  independent  experts  and 


72  WELDING  AND   CUTTING  METALS 

well-known  engineers,  show  the  relative  strength  of  the 
"  Thermit "  rail  joint  compared  with  the  rail  itself,  and  proves 
that  the  running  surface  of  the  rail  is  not  chemically  altered 
during  the  process  of  welding,  and  that  the  electrical  con- 
ductivity is  higher  than  that  of  a  joint  with  fish  plates  and 
bonds. 

A.  Tests  made  for  Leeds  Corporation  Tramways. 

Eails  supported  5  ft.  centre  to  centre,  test  made  with  10  in. 
ram,  2  in.  bearing  on  head  of  rail. 

Up  to  28  tons,  no  deflection,  and  then  F\  in. 
,..  30  „  jfein. 
„  40  „  gV  in. 
„  50  ,,  3%  in. 
,,  55  „  ^  in. 
M  60  „  i  in. 

Test  was  then  stopped,  and  it  was  found  that  there  was  no 
permanent  set  whatever. 

Pressure  brought  on   again   to   65   tons,  still   only   J   in. 
deflection. 

At  68  tons  rail  still  sound. 
,,70    ,,       ,,    broke,  not  through  the  weld. 

B.  Second  Test  made  for  Leeds  Corporation  Tramways. 

Hydraulic  test ;  dead  load ;  5  ft.  bearings,  10  in.  ram,  2  in. 
bar  on  head  of  rail. 

RAIL    WITHOUT    JOINT. 

85  tons    .  T3^  in.  set. 

90    „.  '.     J       „ 

y&    ,,      ..        *        .        •     ^      55 

and  slight  fracture. 


ALUMINO-THERMIC  WELDING  73 

RAIL  WITH  "  THERMIT"  WELDED  JOINT. 
Up  to  60  tons  no  permanent  deflection. 
Safe  dead  load  at  68  tons. 

70  tons  fractured  at  side  of  the  weld,  the  welded  portion 
remaining  intact. 

FISH    AND    SOLE    PLATE    JOINT. 

Fish  plates  62  Ibs.  per  pair,  2  ft.  long,  six  1  in.  bolts ;  sole 
plate  46  Ibs.,  2  ft.  x  8  in.  x  f  in.,  twelve  f  in.  bolts. 
Permanent  set  at  85  tons  f  in. 
90    „     £    „ 
Fractured  at  102  tons. 

Report   of  the    Tensile  Test  carried  out  at  Phoenix  Works, 
llth  May,  1903,  on  "Thermit"  welded  Rail. 

Test  pieces  of  equal  size  (diameter  f  in.,  area  0*48  sq.  in.) 
were  taken  from  the  head  of  the  rail. 

Un welded  Eail.  Thermit  Welded  Eail. 
Limit  of  elasticity 

27,000  Ibs.  =  26-1  tons  per  sq.  in.  26,400  Ibs.  =  24'5  tons  per  sq.  in. 
Maximum  strain 

49, 720  Ibs.  =46-09     ,,         ,,  43,560  Ibs.  =  40-4        „ 

Elongation                     13  per  cent.  4  per  cent. 

Dimension  of  f  racture  ^  in.  |J  in. 

Compression                  16-5  per  cent.  4  per  cent. 

Eesult  shows  that  the  welded  part  has  87*75  per  cent,  of  the 
strength  of  the  original  material,  which  is  very  satisfactory 
indeed.  The  test  was  carried  out  in  the  presence  of  Engineer 
Kurz,  of  the  above  works. 

(Signed)         H.  TIEMANN, 

Engineer. 
Essen  Ruhr, 

12«/*  May,  1903. 
P.S. — It  should  be  noted  that  the  above  test  refers  to  the  rail 


74  WELDING  AND   CUTTING  METALS 

without  the  ring  of  "  Thermit  "  iron,  by  which  it  would 
be  materially  strengthened. 

Tests  showing  the  Relative  Resistance  of  "Thermit"  Joints 
compared  with  Fish  Plate  Joints  and  Bonds. 

(A.)  Test  made  on  a  Leeds  section  of  rail,  100  Ibs.  per  yard. 
The  readings  below  are  the  mean  of  several: 
Eesistance  of  8  ft.  of  solid  rail  alone  .         .     "00006772  ohms. 
8  „         with  "  Thermit " 

joint       .         .     -0000712       „ 
8  „         with  "Thermit" 

joint  and  one 

bond       .         .     -0000678       „ 
,,  8  ,,         with     fish     and 

sole  plates  only     '0001051 
,,  8  ,,  with  fish  and 

sole  plates  and 
one  bond         .     '0000875 
,,  8  ,,     .    with     fish     and 

sole  plates  and 
two  bonds       .     '0000776 

The  resistance  per  foot  of  solid  rail     .         .     '000008465  „ 
The  bonds  used  were  4/0  B.  &  S.  Chicago  type. 

(B.)  Test  made  by  Mr.  J.  Lord,  Borough  Engineer,  Halifax 
(1904)  : 

Weight  of  rail,  96  Ibs.  per  yard. 

Eesistance  of  8  in.  solid  rail  ....  '000067  ohms. 

"  Thermit"  welded  joint,  same  length  of  rail  '000072      ,, 

„       with  one  bond          .  '000067      „ 
Fish  plates,  sole  plate  and  two  bonds,  newly 

constructed      .         .         .         .         .         .  -000078      ,, 

Ditto,  after  two  years     .  ,        ,        .  '000095      „ 


OF    THE 

UNIVERSITY 

OF 


ALUMINO-THEEMIC  WELDING 


75- 


(C.)  Test  made  by  Mr.  I.  E.  Winslow,  Consulting  Engineer 
to  Coventry  Electric  Tramways  Co.  (1905). 

Eesistance  of  consecutive  "Thermit"  joints,  4  ft.  rail  80  lbs_ 
per  yard,  with  joint,  also  4  ft.  of  rail  without  joint. 


Eesistance  of  joint  in  ohms. 


1. 

•0000455 

2. 

•0000446 

3. 

•0000476 

4. 

•0000468 

5. 

•0000464 

6. 

•0000405 

7. 

•0000458 

Eesistance  of  rail  in  ohms. 
•0000420 
•0000392 
•0000415 
•0000391 
•0000375 
•0000410 
•0000365 


Average  1 .0000453  ohms, 
resistance) 


Conductivity  Test. 

LEEDS    CITY    TRAMWAYS. 

Conductivity  test  of  "Thermit"  welded  rail  joint  on  near 
rail,  inward  track,  opposite  St.  Thomas  Street,  North  Street, 
Leeds. 

This  track  was  put  down  in  July,  1903,  and  has  since  been 
in  continuous  use. 


Reading. 

4  ft.  rail. 

4  ft.  rail  with  joint 
and  bond. 

Equivalent  length  of 
rail  with  same  resist- 
ance as  joint  and 

Per  cent, 
greater  con- 
ductivity than 

A. 

V.  Drop. 

A. 

V.  Drop. 

bond. 

rail  itself. 

1 

284 

•0085 

284 

•008 

3-76  ft. 

5-9 

2 

252 

•0075 

252 

•00725 

3-86  ,, 

3'5 

3 

252 

•0075 

252 

•00725 

3-86  ,, 

3-5 

76 


WELDING  AND   CUTTING  METALS 


1 

Reading. 

4  ft.  rail. 

4  ft.  rail  with  joint, 
but  without  bond. 

Equivalent  length  of 
rail  with  same  resist- 

Per  cent,  less 
conductivity 

A. 

V.  Drop. 

A. 

V.  Drop. 

bond. 

itself. 

4 

224 

•0065 

224 

•007 

4-3  ft. 

7-5 

5 

100 

•0025 

100 

•00275 

4'4  „ 

10-0 

Conductivity  of  joint  with  bond  is  4'3  per  cent,  better  than 
the  rail  itself. 

Conductivity  of  joint  without  bond  is  8*75  per  cent,  lower 
than  the  rail  itself. 

NOTE.  —  The  figures  for  current  denote  the  amperes  applied, 
but  as  the  tests  were  made  with  rail  in  position  and  therefore 
not  isolated,  a  proportion  would  pass  round  the  tie-bars  and 
cross-bonds. 

J.    BURBRIDGE, 

Chief  Electrical  Engineer. 
Leeds, 

29t7*  July,  1905. 


Chemical  Test. 

Analysis  of  rails  welded  by  alumino-thermic  process  at 
Leeds,  made  by  Messrs.  Walter  Scott,  Limited,  Leeds  Steel 
Works,  25th  March,  1903. 

Three  separate  drillings  for  analysis  were  taken  from  the 
Leeds  rail  which  was  tested  under  our  machine. 

No.  1.  Sample  was  taken  from  the  end  of  the  rail  away 
from  the  joint. 

No.  2.  Sample  was  taken  from  the  end  of  the  rail  at  the 
joint. 

No.  3.  Sample  was  taken  from  material  composing  the 
joint,  which  was  slightly  honeycombed  in  appearance. 


ALUMINO-THEKMIC  WELDING 


77 


No.  1. 

No.  2. 

No.  3. 

Carbon   . 

•52    per  cent. 

•50    per  cent. 

•18    per  cent. 

Phosphorus    . 

•08 

•08 

•08 

Manganese 

•93 

'94 

•23 

Sulphur  . 

•059       „ 

•058 

•061       „ 

Silicon    . 

•019       „ 

'018       „ 

•170       ,. 

I  find  that  the  welding  has  not  made  any  difference  in  the 
hardness  of  the  head  of  the  rail.  It  is  quite  evident  that  the 
material  forming  the  joint  is  much  softer  than  the  rail. 

(Signed)         EGBERT  HAMILTON. 


MANCHESTER  CORPORATION  TRAMWAYS. 

TESTING  OF  TRAM  KAILS. 

Bending  Tests. 


Description. 

Span. 

Loads 
elastic  limit. 

Bending 
moment. 

Solid  rail        

10ft. 

28,200 

70,500 

Fishplate  jointed  rail     . 

10    ., 

10,000 

25,000 

"  Thermit  "  jointed  rail  .         .         . 

10   „ 

25,000 

62,500 

Solid  rail        

5   „ 

74,000 

92,500 

"  Thermit  "  jointed  rail  . 

6    „ 

42,000 

63,000 

Chemical  Tests. 


Ordinary  steel  rail. 

"  Thermit  "  weld. 

Drillings  from  rail  head 
near  welded  joint. 

Drillings  from  rail 
head  away  from 
welded  joint. 

Iron   .         .  98-520 
Manganese     0'865 
Phosphorus    0-042 
Sulphur      .     0-054 
Silicon        .     0-021 
Carbon       .     0-498 
Arsenic       .     trace 

Iron    .         .  97-82 
Manganese   trace 
Phosphorus      ,, 
Sulphur      .     0-02 
Silicon  and 
Insoluble    0'51 
Carbon       .     0-11 
Aluminium     1'48 

Iron   .         .  98-3743 
Manganese     1*009 
Phosphorus     0'067 
Sulphur      .     0-059 
Silicon       .     0-0027 
Carbon       .     0-488 

These  analyses  indicate 
composition  of  the  st 

Iron   .         .  98-331 
Manganese    1-038 
Phosphorus    0'065 
Sulphur      .    0-058 
Silicon        .    0-018 
Carbon       .    0-490 

s  no  alteration  in  the 
eel  in  the  rail  head. 

78 


WELDING  AND  CUTTING  METALS 


Hardness  Tests. 


Load  on  die 
in  tons. 

Welded  rail. 
Length  of  indentation  produced. 

Away  from  joint. 

Close  to  joint. 

0-25 
0-50 
0-75 

0-26  in. 
0-32  „ 
0-37   „ 

0*26  in. 
0-32  „ 
0-36  „ 

Metal  tested  from  head  of  rail. 

The  relative  hardness  was  determined  by  measuring  the 
lengths  of  indentations  made  by  a  hardened  steel  die  with  a 
curved  edge  struck  to  a  radius  of  1  in.,  and  having  a  cutting 
edge  whose  angle  was  50°. 

From  these  results  it  would  appear  that  there  is  no  appre- 
ciable difference  in  the  hardness  of  the  surfaces. 

J.  M.  MCELROY, 

General  Manager. 
29th  November,  1906. 

A  few  instances  of  general  repairs  actually  carried  out  will 
give  an  idea  of  the  applications  of  the  "  Thermit  "  process. 

Figs.  24  and  25  show  a  repair  to  an  axle  gear  of  a  200  h.p. 
traction  motor.  This  was  a  new  gear  which  had  never  been 
in  service,  but  after  it  had  been  cut,  blowholes  were  found  in 
the  casting  which  practically  severed  the  ends  of  three  teeth 
from  the  rim.  These  were  not  apparent  in  the  blank,  hence 
all  the  workshop  expenses  had  been  incurred.  The  defective 
halves  of  the  three  teeth  were  chipped  out,  and  a  solid  block  of 
"  Thermit "  steel  cast  in,  as  shown  in  Fig.  24.  The  cutter  was 
then  run  through,  leaving  a  perfect  gear,  as  seen  in  Fig.  25. 
This  gear  is  now  in  constant  use  on  one  of  the  London  electric 
railways. 


ALUMINO-THERMIC  WELDING 


79 


FIG.  24. — Eepair  before  Machining.  FIG.  25. — Finished  Eepair. 

Figs.  26  and  27  show  the  application  of  the  "Thermit" 
process  to  large  marine  repairs. 

The  s.s.Rockton,  tonnage  1,971  tons,  then  owned  by  the  Austral- 
asian Steam  Navigation  Company,  of  Sydney,  entered  Mort's 
Dock,  Sydney,  on  Wednesday,  5th  January,  1905.  On  examina- 
tion it  was  found  that  the  keel  of  the  cast-steel  stern  frame 
had  three  distinct  fractures,  each  about  6  ins.  apart,  the  first 
fracture  being  about  12  ins.  from  the  stern  post.  These 
fractures  were  opened  1  in.  wide  by  drill  and  chisel  until 
solid  metal  was  met  with  for  allowing  the  "Thermit"  steel 
to  flow  into. 

The  mould  box,  consisting  of  three  parts,  was  manufactured 
of  J  in.  plate,  stiffened  by  angle  irons,  at  Mort's  Dock  during 
Thursday,  and  the  mould  formed  therein  with  clay  and  sand 
during  that  night  and  placed  in  the  drying  chamber.  After 
the  fractured  part  of  the  stern  post  had  been  heated  to  a  dull 
red,  the  mould  was  carefully  placed  in  position  on  Friday,  well 
packed  with  moist  sand,  and  the  crucible  erected  above  the 
inlet  of  the  mould. 


80 


WELDING  AND   CUTTING  METALS 


The  crucible  was  then  closed  in  the  customary  manner  by  an 
asbestos  and  iron  washer  with  J  in.  magnesia  sand  on  top  of  it, 
and  charged  with  1,200  Ibs.  of  "'Thermit"  mixed  with  120  Ibs. 


Fia.  26. — Cracks  in  Stern  Frame  opened  up  for  Welding. 

of  steel  punchings,  on  top  of  which  \  oz.  of  ignition  powder 
was  placed.  At  5.55  p.m.  the  match  was  put  to  the  ignition 
powder.  The  reaction  lasted  for  forty-five  seconds,  after 
which  the  crucible  contained  in  the  bottom  part  720  Ibs.  liquid 


ALUMINO-THERMIC  WELDING 


81 


"Thermit"  steel  of  a  temperature  of  5,400°  Fahr.  and  about 
600  Ibs.  of  liquid  slag  flowing  on  top  of  the  liquid  steel.  After 
waiting  for  a  further  thirty  seconds  the  lever  underneath  the 


FIG.  27. — Finished  Weld. 

crucible  was  pressed  and  the  liquid  steel  allowed  to  flow  into 
the  mould. 

From  the  time  of  placing  the  match  to  the  ignition  powder 
until  the  last  drop  of  molten  steel  had  left  the  crucible  and 


w. 


82  WELDING  AND   CUTTING  METALS 

flown  into  the  mould  If  minutes  had  elapsed.  The  mould  was 
opened  five  hours  later,  when  it  was  found  that  the  weld  was 
a  perfect  one,  the  Thermit  steel  had  entirely  amalgamated 
with  the  metal  of  the  stern-frame  and  formed  one  homo- 
geneous mass  therewith.  The  whole  welding  was  then 
annealed  for  twelve  hours,  when  the  runner  and  two  risers, 
which  were  formed  by  the  shape  given  to  the  mould,  were 
trimmed  off.  The  toughness  of  the  Thermit  steel  and  the 
ideal  amalgamation  of  the  two  metals,  viz.,  the  Thermit 
steel  and  the  metal  of  the  stern-frame,  was  much  commented 
on  by  the  leading  marine  engineers,  marine  surveyors,  and 
managers  of  the  various  steamship  companies,  who  witnessed 
the  performance. 

By  this  weld  the  opened  up  cracks  were  filled  and 
welded  with  Thermit  steel,  and,  at  the  same  time,  a  steel 
collar  24  ins.  long  and  2^  ins.  thick  at  each  side,  2  ins. 
thick  at  the  top  and  f  in.  at  the  bottom  was  cast  round  the 
entire  fractured  part  of  the  stern-frame,  and  pronounced  by 
the  N.S.W.  Government  and  Lloyd's  surveyors  as  a  perfect 
repair.  Anyone  knowing  the  nature  and  magnitude  of  such 
repairs  as  the  one  performed  on  the  s.s.  Rockton,  must  reflect 
on  the  speed  with  which  this  repair  has  satisfactorily  been 
accomplished  by  Thermit,  namely,  within  three  days  from  the 
time  the  steamer  floated  into  the  dock  until  ready  for  leaving 
again. 

BLAU  GAS  WELDING. 

The  application  of  Blau  gas  for  welding  .purposes  is  being 
introduced,  but  there  are  yet  no  data  as  to  results  obtained. 

BRAZING,  LEAD  BUENING,  AND  SOLDERING. 

Brazing  consists  in  uniting  metal  parts  by  flowering  melted 
brass,  technically  called  spelter,  between  them.  It  is  practically 


LEAD  BURNING  83 

identical  with  soldering  except  that  spelter  is  substituted 
for  solder  and  that  a  much  greater  degree  of  heat  is  necessary. 
In  the  greater  heat  required  to  melt  spelter  lies  one  of  the 
advantages  which  brazed  work  possesses  over  that  which  is 
soldered,  the  finished  work  enduring  more  heat  without 
breaking  or  weakening,  but  the  chief  advantage  lies  in  the 


superior  strength  and  its  applicability  to  a  large  variety 
of  uses. 

Lead  burning  is  often  made  by  autogenous  welding,  using 
hydrogen  or  coal  gas  as  the  combustible  gas  in  conjunction 
with  oxygen.  Hydrogen  is  largely  used  abroad  for  welding  of 
lead  accumulators ;  more  convenient,  however,  is  the  use  of 
coal  gas,  as  generally  more  easily  obtainable. 

The  oxy-coal  gas  blowpipe  introduced  by  the  British  Oxygen 
Company  is  now  extensively  used  by  lead  burners.  It  is  con- 
structed on  the  injector  principle.  By  its  use  oxygen,  delivered 

G  2 


84  WELDING  AND  CUTTING  METALS 

under  slight  pressure  from  a  trade  cylinder,  is  caused  to  draw 
coal  gas  direct  from  the  ordinary  town  supply,  and  then  eject 
the  mixed  gases  in  the  right  proportion  through  the  nozzle  of 
the  blowpipe.  The  use  of  pure  oxygen  instead  of  air  for  com- 
bustion with  this  blowpipe  enables  coal  gas  to  be  employed 
instead  of  hydrogen,  as  the  combustible  gas. 

It  is  suitable  for  ordinary  flat  work,  horizontal  and  upright 
joints,  overhead  patching,  and  the  jointing  of  ordinary  lead 
piping. 

The  illustration  (Fig.  28)  shows  a  man  fully  equipped  with 
everything  required  by  this  system  for  a  day's  lead  burning 
in  any  place  where  a  supply  of  ordinary  town's  gas  can  be 
obtained. 

Relative  Advantages  of  the  Systems. 

(1)  Economy. 

To  supply  the  requirements  of  one  lead  burner  the  com- 
parative cost  per  week  of  the  two  systems  is  approximately  as 
under : — 

Hydrogen-Air  System  £    s.     d. 

Zinc  and  sulphuric  acid   -.         .         .     0  11     0 
Boy's  wages       .         .         ,         .         .     0  10     0 


Total  .         ."  V        .£110 

Oxy-Coal  Gas  System.  £    s.     d. 

Oxygen  delivered  in  cylinder  on  the 

user's  works  .         .         .  .     0  10     0 

Coal  gas  from  town  supply  .         .006 

Total  saving  per  week          .  £0  10     6 

(2)  The  hydrogen  generator  is  dispensed  with. 

(3)  The  air  bellows  is  dispensed  with,  and  consequently  the 
services  of  a  boy  are  not  required. 


LEAD  BUKNING 


85 


(4)  Instead  of  having  to  move  a  heavy  hydrogen  generator 
and  air  bellows  from  one  job  to  another,  it  is  generally  only 
necessary  to   move   a   light  cylinder  containing  the  oxygen 
required. 

(5)  No  apparatus  to  get  out  of  order,  involving  expensive 
delays  and  repairs. 

(6)  As  no   zinc   or   sulphuric   acid   are  used,  there  is  no 


FIG.  29. — Oxy-Coal  Gas  Blowpipe. 

deleterious  matter  to  be  carried  through  the  blowpipe  to  act 
injuriously  on  the  lead  seam. 

(7)  No  pre- warmer  or  "  fou-fou  "  required  on  heavy  work. 
The  blowpipe  flame  is  so  hot  that  even  heavy  lead  in  wet 
and  cold  positions  can  be  burned  in  situ  without  pre-heating. 

(8)  No  gas  generated  when  the  blow- 
pipe is  not  in  use,  and  consequently  there  is 
no  waste  of  gas,  and  no  charge  to  withdraw 
overnight. 

(9)  In  places  where  a  supply  of  town's 
gas  is  not  available,  coal  gas  or  hydrogen 

can  also  be  obtained  from  the  British  Oxygen  Company  in 
cylinders,  or  the  oxygen  may  be  used  advantageously  with  a 
hydrogen  generator. 

In  the  oxy-coal  gas  system  of  lead  burning  compressed 
oxygen  takes  the  place  of  air,  and  ordinary  town's  gas  takes 
the  place  of  the  hydrogen  used  in  the  old  system. 

The  blowpipe  is  an  ordinary  lead  burner's  blowpipe  with 
two  inlets,  one  for  oxygen  (0)  and  the  other  for  coal  gas  (H). 


FIG.  30.— Shoulder 
Taps. 


86  WELDING  AND   CUTTING  METALS 

The  oxygen  inlet  is  constructed  in  the  form  of  an  injector,  by 
means  of  which  the  pressure  of  the  oxygen 
(about  15  Ibs.  per  square  inch)  coming 
from  the  cylinder  through  a  regulator 
(Fig.  31)  is  made  to  suck  the  necessary 
supply  of  coal  gas  through  the  inlet  H  of 
the  blowpipe,  and  deliver  the  gases  well 
mixed  and  under  sufficient  pressure  to 
the  burner  nozzle.  The  blowpipe  (Fig.  29) 

FIG.  31.— Endurance  is  constructed  in  two  sizes,  each  being 
provided  with  two  nozzles  and  a  wind 

shield,  the  full  equipment  being  capable  of  dealing  with  all 

weights  of  lead. 

CHEMICAL  WELDING  OF  IRON  AND  STEEL 
AT  A  Low  TEMPERATURE. 

At  the  Franco-British  Exhibition  the  Societe  des  Plaques 
et  Poudres  a  Souder,  J.  Laffitte  exhibits  some  specimens  of 
their  welded  articles  of  iron  and  steel. 

The  welding  agent  used  consists  of  thin  welding  plates, 
principally  of  copper,  chequered  and  sectioned  so  that  they 
may  easily  be  divided  by  hand  according  to  requirement,  or 
of  a  flux  in  form  of  a  powder,  different  for  welding,  brazing, 
tempering,  and  which  is  sold  in  tins.  The  welding  plate  is 
placed  between  the  two  pieces  to  be  welded  together,  put  into 
the  ordinary  coal  fire  and  heated,  and  then  hammered 
together.  The  use  of  these  welding  plates,  it  is  said, 
ensures  in  every  case  an  absolutely  homogeneous  weld, 
equal  to  the  original  metal. 

In  exceptional  cases,  where  the  rigidity  of  the  plate  does  not 
lend  itself  to  the  work  to  be  done,  such  as  cementing  a  flaw, 
welding  in  a  hole,  etc.,  the  welding  powder  is  successfully 
employed. 


WELDING  87 

COAL  GAS  WELDING. 

The  ordinary  coal  or  illuminating  gas  may  be  used  for 
welding.  The  arrangement  is  extremely  simple  and  inexpen- 
sive, as  the  heavy  steel  cylinder  containing  any  of  the  com- 
bustible gases  is  substituted  for  a  rubber  tube,  by  means  of 
which  the  gas  is  conveyed  from  the  place  of  supply  (from  an 
ordinary  gas-pipe  tap)  to  the  blowpipe  as  fully  described 
under  "  Brazing,"  page  82. 

The  great  advantage  possessed  by  the  coal  gas  over  any  other 
combustible  gas  is  to  be  found  simply  in  the  cheapness  of  the 
installation,  making  it  thus  the  cheapest  welding  system. 

The  application  of  coal  gas  is,  however,  limited  to  brazing, 
and  welding  of  lead,  bronze,  brass,  etc.  How  far  it  is  suitable 
for  welding  of  iron  and  steel  is  a  question  to  be  considered. 

WELDING  OF  COPPER. 

The  welding  of  copper  requires  a  larger  sized  blowpipe  than 
that  for  iron  of  corresponding  thickness,  by  reason  of  the 
greater  conductivity  of  copper.  A  flux  is  always  required, 
pulverised  aciduni  boricum  generally  being  used  for  such 
purpose.  The  weld  should  always  be  mechanically  treated  as 
soon  as  it  has  cooled. 

The  welding  of  copper  is  a  substitute  for  brazing  in  copper 
work  of  various  descriptions.  By  means  of  the  coal-gas  blow- 
pipe, copper  pipes  and  many  kinds  of  sheet-copper  structures 
can  be  fused  together  as  one  pipe,  where  brazing  would  other- 
wise be  necessary. 

A  Parisian  metallurgist  claims  to  have  perfected  a  process 
of  welding  copper  to  steel  wire  so  as  to  make  a  non-corrosive 
coating.  Many  advantages,  it  is  said,  will  result  from  the  use 
of  this  new  wire,  such  as  high  tensile  strength  and  elasticity, 
combined  with  smaller  surface  exposed  to  wind  and  sleet  than 
would  be  the  case  with  iron  wire  at  the  same  conductivity. 


88  WELDING  AND   CUTTING  METALS 

This  wire,  it  is  said,  is  especially  useful  over  long  spans,  as 
pole  intervals  may  be  much  greater  where  it  is  used.  Compare 
with  "  Brazing,"  page  82. 

ELECTRIC  WELDING. 

Electric  welding  is  gaining  rapid  acknowledgment,  the  more 
as  its  great  advantages  combined  with  inexpensive  machinery 
and  easy  manipulation  are  becoming  known.  It  has,  during  the 
last  few  years,  developed  into  many  branches  and  industries 
which  at  the  time  of  its  inception  were  quite  undreamt  of. 

The  erroneous  opinion  that  electric  welding  is  expensive 
and  difficult  to  manipulate,  based,  no  doubt,  upon  results  of 
antiquated  systems,  lack  of  technical  knowledge,  and  general 
inexperience,  is,  however,  easily  overcome  by  simple  investiga- 
tion. It  should  not  be  forgotten  that  since  the  first  introduc- 
tion of  electric  welding  some  fifteen  years  since,  great 
improvements  have  been  made  and  that  large  works  have 
been  built  with  the  sole  object  of  building  suitable  machines 
for  electric  welding,  with  the  result  that  the  machines  have 
reached  almost  perfect  simplicity,  being  generally  automatic 
in  their  working,  reducing  thereby  manual  labour  to  a 
minimum  and  limiting  technical  knowledge  to  that  possessed 
by  every  mechanic. 

There  are  several  methods  of  electric  welding,  differing  from 
each  other  both  in  principle  and  application — Arc  u- elding 
being  a  surface  welding,  and  Resistance  welding  being  a  sectional 
welding  depending  upon  the  internal  resistance  which  a  body 
presents  to  the  passage  of  the  electric  current. 

Arc  ivelding  appears  to  have  been  first  employed  by  De 
Meritens,  in  1881.  In  this  instance  leaden  pieces  designed 
to  be  united  in  the  form  of  storage  battery  plates  were 
arranged  together  as  an  extended  positive  electrode,  and  an 
arc  was  drawn  between  them  and  a  negative  carbon  rod 


ELECTEIC  WELDING  S9 

manipulated  by  means  of  an  operating  handle.  Part  of  tlie 
heat  energy  of  the  arc  served  to  melt  the  lead  and  cause 
union  of  the  adjacent  pieces,  but  much  the  larger  proportion 
of  the  energy  escaped  by  radiation  and  connection.  The 
electric  arc  was  thus  akin  to  a  gas  blowpipe  as  commonly 
used  in  lead  burning  in  the  construction  of  tanks  for  the 
chemjcal  industries. 

Following  De  Meritens,  heating  by  electric  arcs  has  been 
applied  to  the  fusing  and  welding  of  metals,  notably  of  iron 
and  steel,  by  Bernardos  and  Olszewski,  Coffin,  and  others. 

When,  as  in  the  Bernardos  and  Olszewski  method,  the 
carbon  electrode  is  made  positive  to  the  work,  carbon  is  trans- 
ported through  the  arc  and  is  likely  to  enter  the  metal 
undergoing  the  process,  which  constitutes  the  negative  pole. 
This  addition  of  carbon  may  render  iron  and  steel  hard  and 
unworkable  and  cause  cracks  to  be  formed  during  the  cooling 
of  the  fused  mass  at  the  joint  or  filling. 

By  the  employment  instead  of  carbon  of  an  electrode  of  the 
same  metal  as  that  of  the  work,  Slavianoff  overcame  this 
difficulty.  The  gradual  melting  of  the  metal  electrode 
furnishes  metal  for  forming  joints,  or  for  repairing  or  supple- 
menting castings  which  are  defective,  such  as  those  which  are 
incomplete  or  contain  blowholes. 

More  recently  the  work  is  made  the  positive  pole,  and  this 
results  in  a  greater  proportion  of  the  energy  than  formerly 
being  expended  in  heating  the  metal  undergoing  the  operation. 

Inasmuch  as  the  conditions  of  energy  supply  for  sustaining 
the  arc  are  but  little  different  from  those  often  found  in  the 
commercial  operation  of  arc  lamps  from  constant  potential 
mains,  arc  welding  may  often  be  practised  by  connections 
made  to  such  mains.  A  steadying  resistance  is  put  in  series 
with  the  fusing  arc  in  a  branch  from  direct  current  lines  at  a 
potential  difference  of  200  volts  or  thereabout. 


i>0  WELDING  AND   CUTTING  METALS 

With  work  such  as  that  to  which  the  Bernardos  and 
Olszewski  method  has  been  found  to  he  applicable,  the 
current  in  the  arc  may  vary  from  150  amperes  up  to  500  or 
.more.  The  potential  across  the  arc  itself  will  generally  be 
from  100  to  150  volts. 

With  the  metal  electrode  used  by  Slavianoff  the  current 
needed  will  be  greater,  and  the  arc  potential  less  than  the 
above  amounts.  It  appears  that  in  certain  cases  the  current 
may  even  surpass  4,000  amperes. 

Werdermann,  in  1874,  proposed  to  deflect  an  electric  arc 
formed  between  the  usual  carbons  by  a  jet  of  air,  forming 
thereby  an  electric  blowpipe. 

More  recently  Zerener  has  in  a  similar  way  employed  an 
arc  deflected  by  a  magnet  as  a  sort  of  blowpipe  for  welding 
iron. 

In  addition,  the  curious  electric  heating  action  first  published 
by  Holio  and  Lagrange  has  been  proposed  for  welding  metals. 

If  a  negative  electrode,  of  a  direct  current  circuit  having  a 
potential  of  100  to  150  volts,  is  of  small  surface  relatively  to 
that  of  the  positive  electrode  and  both  are  immersed  in  a 
liquid  bath,  such  as  a  solution  of  potassium  or  sodium 
carbonate,  the  surface  of  such  negative  electrode  glows  with 
light,  gas  bubbles  arise  from  it,  and  the  electrode  itself  heats 
rapidly  in  spite  of  its  immersion  in  cold  liquid.  A  bar  of 
iron  used  as  the  negative  electrode  may  thus  be  brought  to 
incandescence  and  removed  for  welding,  or  it  may  even  be 
melted  under  the  liquid  of  the  bath.  The  loss  of  heat  in  such 
a  liquid  heating  process  is  necessarily  somewhat  great. 

While  the  moderate  application  of  these  arc  processes  for 
fusing  and  welding  iron  and  steel  has  been  made,  the  range  of 
operations  to  which  they  are  suitable  is  somewhat  limited, 
and  their  success  depends  largely  upon  the  skill  of  the  work- 
man. He  must  protect  not  only  his  eyesight  but  also  the 


ELECTRIC  WELDING  91 

surface  of  his  body  from  the  glare  of  the  large  arc,  and 
also  avoid  the  irritating  vapours  which  arise  from  the  flame. 
At  the  same  time  vigorous  ventilation  cannot  be  employed, 
for  motions  of  the  air  tend  to  disturb  the  arc  and  render  the 
work  more  difficult.  A  large  proportion  of  the  energy  is 
radiated  or  carried  off  in  the  hot  gases  from  the  arc.  To 
these  energy  losses  must  be  added  that  due  to  the  use  of  the 
steadying  resistance  for  obtaining  stability  in  the  current  of 
the  arc. 

On  the  other  hand,  the  appliances  needed  for  arc  fusing  or 
welding  are  simple,  and  the  source  of  current  energy  often 
conveniently  found  in  existing  electric  circuits. 

The  Resistance  system  of  electric  welding  seems  to  have 
been  first  introduced  by  Professor  Elihu  Thomson,  in  1877, 
whilst  making  some  experiments  in  the  laboratory  of  the 
Franklin  Institute,  Philadelphia,  discharging  a  Leyden 
battery  through  the  fine  wire  winding  of  an  induction  coil. 
The  fine  wire  thus  became  a  high  potential  primary,  the 
ends  of  the  coarse  wire  winding  being  brought  into  light 
contact  and  welded  together,  so  that  it  took  some  little 
force  to  separate  them.  From  this  early  experiment  was 
developed  the  now  familiar  "  Thomson  process."  No  electric 
arc  is  employed,  but  the  heat  which  effects  the  welding  is 
solely  due  to  the  resistance  of  those  parts  of  the  metal  pieces 
at  the  contact  where  they  are  to  be  welded  together.  This 
resistance  is  of  course  extremely  low,  and  the  delivery  of 
sufficient  energy  for  heating  and  welding  is  the  result  of  the 
passage  of  relatively  enormous  currents.  Their  potential  is 
only  two  or  three  volts,  more  or  less. 

The  metal  pieces  to  be  welded  together  are  held  respectively 
in  massive  clamps  or  vices  of  highly  conducting  metal  such  as 
copper,  with  a  slight  portion  only  of  each  piece  projecting  to 
form  the  joint.  These  projections  of  the  pieces  are  brought 


92  WELDING  AND   CUTTING  METALS 

together  in  firm  contact,  for  which  purpose  at  least  one  of  the 
clamps  is  made  movable  toward  and  from  the  other,  both  of 
them  being  mounted  on  a  firm  support.  The  pieces  having 
been  adjusted  to  meet  in  correct  relation  for  the  subsequent 
formation  of  the  weld  uniting  them,  an  electric  current 
sufficient  in  amount  to  heat  the  meeting  portions  of  the  pieces 
to  the  temperature  at  which  they  soften  and  unite,  is  passed 
from  clamp  to  clamp,  thus  traversing  the  joint  and  the  short 
projecting  portions  of  the  pieces  between  the  clamps.  So 
heavy  is  the  current  at  command  that  a  solid  bar  without 
break  spanning  the  space  between  the  clamps  could  be  heated 
and  melted.  The  completion  of  the  weld  after  heating  is 
effected  by  pressure  exerted  to  force  one  clamp  towards  the 
other,  which  results  in  a  slight  upsetting  or  extrusion  of  metal 
at  the  weld,  called  a  burr. 

For  copper  a  pressure  of  about  600  Ibs.  per  square  inch 
of  section  is  usual,  while  with  iron  it  is  1,200,  and  with  tool 
steel  1,800  Ibs.  or  more. 

The  welding  clamps  are  in  practice  carried  directly  upon 
the  secondary  terminals  of  a  special  welding  transformer. 

The  various  applications  of  the  welding  by  resistance  require 
different  machines,  according  to  the  shape  and  size  of  the 
work.  Mr.  Hugo  Helberger  has  kindly  lent  some  of  the 
following  blocks. 

The  current  may  be  supplied  from  an  already  existing 
generating  plant,  or  a  new  plant  (primary  plant)  may  be 
erected.  The  most  advantageous  form  of  current  is  single- 
phase  alternating  current ;  in  this  case  the  machines  may  be 
connected  to  the  electrical  supply  as  easily  as  an  ordinary 
incandescent  lamp.  In  the  case  of  two-  or  three-phase  current 
the  machine  must  be  connected  to  one  phase,  care  being  taken 
that  this  phase  is  not  overloaded  in  comparison  to  the  other 
phases.  If  several  welding  machines  are  required  these  can 


ELECTEIC  WELDING  93 

be  distributed  among  the  different  phases,  and  the  use  of  the 
multi-phase  current  presents  no  difficulties. 

In  cases  where  no  alternating  current  is  obtainable,  only 
direct  current  being  present,  or  where  no  electric  current  at 
all  is  obtainable,  a  single-phass  generator  must  be  installed, 
or  direct  welders,  which  are  built  as  current  generating  machines, 
may  be  used,  always  assuming  the  presence  of  driving  power. 
Direct  welders  are  only  built  up  to  10  h.p. ;  above  this,  separate 
generators  must  be  employed. 

Motor-generators  may  be  utilised  where  direct  current  is 
obtainable.  The  direct  current  is  transformed  into  a  suitable 
alternating  current. 

Each  welding  machine  consists  of  two  main  parts,  i.e.,  the 
welding  apparatus  and  the  transformer.  These  two  parts  are 
rigidly  secured  to  each  other  and  built  as  one  piece,  whereby 
a  higher  efficiency  is  attainable  than  if  each  part  were  built 
separately. 

The  welding  apparatus  is  essentially  an  arrangement  of 
mechanical  parts  and  consists  of  the  contact  device,  the 
clamping  arrangement  and  the  means  for  exerting  the 
necessary  pressure.  Kapid  working  being  the  chief  advan- 
tage of  electric  welding  machines,  these  devices  are  generally 
most  carefully  constructed,  even  in  the  smallest  detail. 

The  construction  of  the  welding  apparatus  with  a  view  of 
reducing  the  time  of  manipulation  to  a  minimum  has  caused 
the  welding  machines  to  be  subdivided  into  universal  welding 
machines  and  special  welding  machines. 

Universal  machines  are  built  in  such  a  manner  that  all  kinds 
of  objects  can  be  welded  therewith  (Figs.  32,  33,  34).  In  order  to 
increase  its  practical  application  the  parts  as  well  as  the 
welding  apparatus  as  a  whole  are  made  interchangeable. 

These  machines  are  chiefly  used  in  constructive  iron  works, 
in  workshops  for  architectural  and  artistic  ironwork,  and  in 


WELDING  AND   CUTTING  METALS 


ELECTRIC  WELDING 


FIG.  33.— Universal  Machine,  Normal  Pattern,  without  Swages. 


96 


WELDING  AND   CUTTING  METALS 


FIG.  34.— Universal  Machine,  with  Automatic  Hammer  and  Adjustable  Anvil  for 
Hand  and  Mechanical  Power. 


ELECTRIC  WELDING 


97 


similar  establishments  for  executing  all  those  kinds  of  welding 
work  which  occur  most  frequently  in  such  works  ;  end  to  end 
welding ;  the  welding  of  pieces  at  an  angle  to  each  other ;  the 
cross-welding  of  wire,  rods,  bands,  square  iron,  L-iron  and  all 
other  kinds  of  profiled  iron  and  steel.  By  changing  the 


EIG.  35. — Hand  Chain  Welding  Machine,  for  Chains  up  to  6  mm.  diameter. 

welding  apparatus  the  machine  can  be  employed  for  welding 
of  tubes  and  hoops  or  rims. 

Special  welding  machines  are  constructed  for  welding  one 
particular  kind  of  article,  and  should  be  selected  in  those 
cases  where  great  numbers  of  the  article  are  to  be  welded, 
for  instance,  chains  (Figs.  35,  36,  37,  38),  buckles  (Figs.  39,  40), 
door-hinges,  hinge-hooks,  hinge-bands,  etc.,  for  doors  and 
cupboards  (Fig.  41) ;  end-to-end  welding  of  flat  hoops,  rings 
(Fig.  42) ;  for  simultaneously  welding  several  pins  or  pieces 


98 


WELDING   AND  CUTTING  METALS 


of  metal  to  discs  or  rings  of  metal,  for  instance,  as  used  in 
watch  and  clock-making  (Fig.  48)  ;  for  point  welding  in 
making  iron  furniture,  grills,  etc.  (Fig.  44);  for  welding 


FJG.  36. — Automatic  Chain  Welding  Machine,  for  Small  Chains. 

pulley-spokes  to  rim  and  hub  (Fig.  45) ;  for  welding  auto- 
mobile and  cycle  rims  (Fig.  46),  and  the  like.  Special  machines 
are  constructed  for  an  infinite  number  of  specialised  purposes. 
In  many  cases,  especially  for  small  articles,  the  special 
machines  may  be  converted  into  automatic  machines.  The 


ELEOTEIC  WELDING 


99 


d 

•3 
jd 
O 


u  2 


100 


WELDING  AND   CUTTING  METALS 


s 

to 


ELECTETC  WELDING 


101 


removal  and  replacement  of  the  articles  is  then  performed  by 
mechanical  means,  or  in  some  cases  by  electro-magnets,  and 


FIG.  39.— Eing  and  Buckle  Welding  Machine,  for  Eidgeless  Welding 
in  Swages,  Machine-driven. 

the  functions  of  clamping  and  releasing,  pressing  together, 
opening  and  closing  the  circuit  are  under  the  influence  of 


102 


WELDING  AND  CUTTING  METALS 


ELECTEIC  WELDING  103 

automatic  relays  connected  with  mechanical  driving  power, 
which  is  applied  or  shunted  off  at  the  right  time  by  frictional 
devices. 

These  automatic  machines  do  not  require  a  special  atten- 
dant, as  one  man  can  attend  to  several  machines  at  the  same 
time.  The  field  of  such  machines  is  limited  by  the  size  and 
weight  of  the  articles  to  be  welded,  and  they  are  therefore 
more  especially  suited  for  welding  small  articles  in  very  large 
quantities,  where  the  occasional  appearance  of  a  defective 
piece  is  of  no  moment.  For  these  machines  it  is  important 
to  have  the  articles  previously  prepared  exactly  alike,  as  even 
a  small  difference  in  the  dimensions  of  the  single  article  leads 
to  unsatisfactory  results. 

The  pressing  together  of  the  hot  metal  at  the  point  of  weld- 
ing results,  as  already  stated,  in  the  formation  of  a  burr, 
which  must  in  most  cases  be  afterwards  removed. 

The  machines  are  sometimes  provided  with  a  device  for 
surrounding  the  point  of  welding,  as  soon  as  the  right 
temperature  has  been  reached,  with  a  swage  (Fig.  39, 
page  101),  whereby  the  welding  is  completed  without  a 
burr ;  such  a  joint  is  especially  strong,  as  the  hot,  soft 
metal  receives  a  lateral  pressure  from  the  swage,  thereby 
greatly  increasing  the  density  of  the  metal  at  the  weld. 

In  case  of  larger  articles  an  automatic  hammer  with  adjust- 
able anvil  can  be  substituted  for  the  swage ;  this  hammer  is 
so  arranged  that  the  burr  can  be  hammered  down  during  the 
continuation  of  the  heat. 

The  energy  and  time  required  for  welding  are  approximately 
proportionate  to  the  sectional  area  of  the  parts  to  be  welded. 
It  is  possible  to  weld  a  given  piece  either  by  using  greater 
power  during  a  short  time  or  by  exerting  a  smaller  power 
during  a  longer  time  ;  but,  in  order  to  ensure  rational  work- 
ing, it  is  necessary  for  time  and  power  to  stand  in  certain 


104 


WELDING  AND   CUTTING  METALS 


proportions  to  each  other,  which  differ  for  different  areas  and 
different  materials. 

The  permanent  working  of  a  machine  increases  the  heating 
of  those  parts  of  the  machine  which  are  nearest  to  the  weld. 
In  order  to  keep  the  heating  within  admissible  limits,  water- 
cooling  is  provided.  If  there  are  no  water  mains  two  tanks 


FIG.  41. — Special  Machine  for  Welding  Door-hinges,  Hinge-hooks, 
Hinge-bands,  etc.,  for  Doors  and  Cupboards. 

may  be  provided,  one  placed  higher  and  the  other  lower  than 
the  machine,  so  that  the  water  from  the  upper  tank  can  flow 
through  the  machine  into  the  lower  tank.  A  moderate  supply 
of  water,  from  20  to  100  litres  per  hour,  is  sufficient,  according 
to  the  size  of  the  machine. 

Primary   Plants. — Electric    welding   machines,   as   already 
stated,  require  alternating  current  for  their  operation.     In  the 


ELECTELC  WELDING  10* 

case  of  direct  welders,  which  can,  however,  only  be  considered 
for  small  types,  the  machine  generates  its  own  alternating 
current,  Even  if  it  is  possible  to  use  such  direct  welders 
for  the  small  size,  it  will  always  be  more  desirable  and  of 


FIG.  42.— Machine  for  End  to  End  Welding  of  Flat  Hoops, 
Rings,  and  similar  Articles. 

greater  advantage  to  provide  separate  welding  machines,  and1 
to  take  the  necessary  alternating  current  from  a  generating 
plant. 

The  machines  can  be  adapted   to  any  existing  plant   for 
alternating  current,  whatever  the  voltage  and  periods. 


106 


WELDING  AND   CUTTING  MliTALS 


Such  a  primary  plant  comprises — 

(a)  The  generator  for  single-phase  alternating  current  with 


PIG.  43. — Machine  for  Simultaneously  Welding  several  Pins  or  Pieces 
of  Metal  to  Discs  or  Eings  oi  Metal  (for  use  in  Watch  and 
Clock  Making). 

•exciting  dynamo,  or  with    separate   excitement   (by  existing 
direct  current) ; 

(b)  The  switchboard,  with  all  necessary  switches,  meters, 
•cut-outs,  and  regulating  apparatus ; 


ELECTEIC  WELDING 


107 


(c)  Tha  connections  between  the  generator,  switchboard  and 
welding  machine. 


The  generator  with  exciting  dynamo  must  be  used  whenever 
no  direct  current  for  the  excitement  is  obtainable.  Existing 
direct  current  makes  the  exciting  dynamo  superfluous. 


108 


WELDING  AND   CUTTING  METALS 


FIG.  45. — Machine  for  Welding  Pulley-spokes  to  Eim  and  Hub. 


ELECTRIC   WELDING 


109 


FIG.  46. — Hoop  and  Rim  Welding  Machine,  specially  suited  for  Weldin< 
Automobile  and  Cycle  Rims. 


110  WELDING  AND   CUTTING  METALS 

The  generators  are  specially  constructed  with  stationary  alter- 
nating current  coils  and  rotating  exciting  coils,  an  arrangement 
which  is  best  adapted  to  withstand  the  unavoidable  current 
impulses  accompanying  the  welding  process.  The  voltage 
and  number  of  periods  is  chosen  with  regard  to  the  require- 
ments of  the  welding  machine  it  works,  and  vary  between  100 
and  500  watts  at  fifty  periods  a  second.  The  generator  should 
be  chosen  large  enough,  so  that  the  continual  change  from 
full  load  to  no  load  will  not  damage  the  machine.  If  several 
welding  machines  are  worked  from  one  generator,  the  total  of 
the  power  required  by  each  single  machine  will  be  sufficient  for 
the  generator,  as  the  average  power  required  for  an  aggregate 
of  welding  machines  is  essentially  less  than  the  total  of  each 
single  power. 

The  welding  machines  are  generally  delivered  mounted 
and  ready  for  working,  requiring  only  the  electrical  connec- 
tions in  as  simple  a  manner  as  that  for  an  incandescent 
lamp. 

Nearly  all  of  the  metals,  even  those  like  antimony  and 
bismuth,  which  are  brittle  and  crystalline,  may  be  joined 
together  by  electric  welding,  and  many  different  metals 
and  alloys  joined  one  to  another.  In  some  cases,  as  with 
high  carbon  steels,  a  flux,  such  as  borax,  is  employed  to 
facilitate  union  at  temperatures  not  high  enough  to  burn  or 
destroy  the  texture  of  the  metal.  Mild  steel  and  iron  welds 
are  usually  made,  as  in  ordinary  forges,  at  welding  heat, 
or  that  which  melts  or  fluxes  the  ordinary  black  oxide 
scale  upon  the  metal.  The  heating  effect  of  the  electric 
current  is  so  perfectly  adjusted  by  regulating  appliances 
that  most  of  the  metals  formerly  regarded  as  unweldable 
yield  good  results.  Even  leaden  pieces,  such,  for  example, 
as  sections  of  lead  pipe,  may  be  joined  together  with  great 
ease. 


ELECTRIC  WELDING 


111 


The  Electric  Welding  Company,  Limited,  sole  owners  of  the 
Thomson  patents  in  the  United  Kingdom,  have  given  the 
following  information  as  to  their  standard  types  of  welders : — 


x  *J 

If 

<& 

ji  s§sss  li  ii  ii  i  1      HI 

Approx. 
Dimensions. 

^     M  S  °  stlrf     ^S^OT'^CNW                   co      co      co 
x-xxxxx      xx      xx      xx      x      x                  x      x 

c°*    ^s^w'w'    g^^^g^SJco             3co°< 

""   X         XXXXX         XX         XX         XX         X         X                          X         X         X 

£!?        5O  if  -O  i-i  —  1         Cf.  I-         f~  TH         -tO         IN         00                             T>         O         Oi 
5         ^  ,J|  ,14  <M  <M        CNC-l         (MCO        COCO         CO         -v                           O        CJ        «) 

I 

3 

60 

i 
1 

^     ^^^               S           d 

02       32020Q                       ^                  ^ 

0        °  °  P                       ,^                  ,° 

Iron  and  Steel. 

d       ddg       --Iso 

^"     ^  ^.s     ^  £.3  S    =          R  '  s:  a 

d             02    ,        02       02^.             -5         c'0         2 
^              0              0        0_C              ^o      --__C        _C 

=0           ^t           oo       w  +*           o      "^  ^      >rH.      '"                    '[•,"•'" 
0              ^              ""!        ^  °^              ^        B'~°.         &        £                         v:         $        & 

^                   O                   OCO                   O)w.OOrH                                CO1^1^ 

J=*  » 

r-T     r-Tm'eo  •*"*"'     -*"t-r     ^-^T     «To"     o"      o"                    o"     o"     o" 

Kind  of  Work. 

•^                         S<~§'E            ^           ^'^'rao^S^'^^E^3 

|!||  lliliii  |»IiiliiTl1ii1ll  i  ill 

&•       QOQUO02       0202       O02       0202       O2       02             02 

y 

2 

o 
I 

y                                     .     .         «j      .                              .                                           ... 

1             1    1               i 
'.  %'••••---&'.  Is  1^   '       1  «  • 

11^      j|  jj  j    1   '       | 

112  WELDING  AND   CUTTING  METALS 

The  above  welders  are  in  some  cases  fitted  with  detachable 
clamps,  so  that  other  kinds  of  work  may  be  welded  by  using 
different  clamps.  Many  other  types  of  welders  are  also  built 
for  special  purposes. 

In  the  earlier  electric  welding  systems  the  operations  of 
-clamping  the  pieces  in  place,  applying  and  cutting  off  the 
electric  current  and  exerting  mechanical  pressure,  were 
usually  manually  controlled.  Machines  more  or  less  auto- 
matic are  now  frequently  employed. 

In  recent  types  adopted  for  rapid  repetition  of  work  upon 
identical  pieces  the  action  is  entirely  automatic  ;  the  machine 
runs  continually  and  its  sequence  of  actions  is  definitely  deter- 
mined by  its  construction.  These  machines  are  power-driven, 
movements  being  imparted  for  clamping  the  pieces  as  they  are 
ied  to  the  machine,  for  closing  the  current  switch,  for  exerting 
pressure  to  complete  the  weld,  for  cutting  off  the  current,  and 
for  releasing  the  pieces  from  the  clamps  after  the  operation. 
In  wire  fence  and  chain  machines,  for  instance,  the  stock  is 
itself  fed  automatically  and  the  welding  continued  until  the 
machine  is  stopped  or  the  material  exhausted. 

The  Thomson  welding  transformer  is  a  construction  like  a 
lighting  transformer,  in  which  the  usual  secondary  circuit 
of  numerous  turns  is  replaced  by  a  very  massive  conductor 
•constituting  ordinarily  only  a  single  turn  around  the  iron 
magnetic  core.  The  primary  or  inducing  circuit  is  similar 
to  that  of  the  ordinary  transformer  for  alternating  current, 
and  it  is  supplied  from  alternating  current  dynamos  on 
lines  as  usual  in  such  work.  The  secondary  conductor  is 
unique  in  character,  being  often  a  bar  or  casting  of  many 
square  inches  of  section  of  copper  of  short  length.  The 
circuit  of  this  single  turn  secondary  is  completed  only  by  the 
meeting  ends  of  the  work  pieces  in  the  clamps.  It  will  thus 
be  evident  that  the  chief  resistance  or  opposition  to  the  flow 


ELECTEIC  WELDING  113 

of  the  low-voltage  current  in  the  single  secondary  turn  will  be 
at  the  proposed  joint  or  weld  between  the  clamps.  Here  it 
is  that  the  transformed  energy  is  for  the  most  part  given 
out  as  heat,  the  section  of  metal  which  can  be  welded  depend- 
ing upon  the  scale  of  the  apparatus  used  and  the  energy  of  the 
primary  source  which  is  available. 

The  welding  transformer  has  found  convenient  application 
in  the  heating  of  metal  pieces  for  forging,  bending,  shaping, 
brazing  or  the  like.  It  has  also  in  the  Lemp  process  been 
divested  of  its  welding  clamps  and  applied  to  the  local  anneal- 
ing of  the  hardened  face  of  armour  plates,  so  as  to  facilitate 
drilling  and  tapping,  or  cutting  into  desired  shapes. 

The  welds  made  by  the  Thomson  process  are  usually  butt 
welds,  though  lap  welds  are  also  made  with  equal  facility.  In 
butt  welding  there  is,  of  course,  an  upset,  burr,  or  extrusion  of 
metal  at  the  joint.  In  many  cases  this  is  not  removed,  and  it 
renders  the  joint  stronger  than  other  adjacent  sections ;  often- 
times the  joint  is  pressed  or  forged  while  still  hot,  so  as  to- 
remove  the  burr  at  the  joint.  In  other  cases  the  joint  is- 
finished  by  riling  or  grinding. 

The  welding  clamps  are  modified  in  form  and  disposition  to 
suit  the  shape  and  size  of  the  pieces  to  be  held,  and  the  pressure 
used  to  effect  the  weld  is  either  manually  applied  by  levers  or 
is  obtained  from  a  strained  spring,  or  again,  in  large  works,  by 
hydraulic  means  under  control  of  suitable  valves. 

The  energy  required  to  effect  electric  welds  naturally  varies 
with  the  size  of  the  pieces  and  with  the  material.  It  also 
depends  upon  the  time  consumed  in  the  work,  which  time  may 
be  made  shorter  or  longer  even  with  exactly  similar  pieces. 

The  following  table  gives  the  results  of  some  tests  made 
upon  different  sections  of  iron,  mild  steel,  brass  and  copper  in 
the  form  of  bars.  The  figures  are  stated  to  be  only  approxi- 
mate. In  general,  working  at  a  greater  rapidity  would  lessen 

w.  i 


114 


WELDING  AND   CUTTING  METALS 


the  total  power  used,  but  require  larger  apparatus    for   the 
increased  output  required  during  the  welding. 

ENERGY    USED    IN    ELECTRIC    WELDING 
BY  THE  THOMSON  PROCESS. 


Material. 

Section. 
Square  inch. 

Kilowatts  in 
primary  of 
welder. 

Time  in 
seconds. 

Total  kilowatt- 
seconds. 

0-5 

8-5 

33 

280-5 

1-0 

16-7 

45 

751-5 

1-5 

23-5 

55 

1292-5 

Iron  and 

2-0 

29-0 

65 

1885-0 

Steel 

2-5 

34-0 

70 

2380-0 

3-0 

39-0 

78 

3042-0 

3'5 

44-0 

85 

3740-0 

4-0 

50-0 

90 

4500-0 

0-25 

7-5 

17 

127-5 

0-50 

13-5 

22 

297-0 

0-75 

19-0 

29 

551-0 

Brass 

1-00 
1-25 

25-0 
31-0 

33 

38 

825-0 
1178-0 

1-50 

36-0 

42 

1512-0 

1-75 

40-0 

45 

1800-0 

2-00 

44-0 

48 

2112-0 

0-125 

6-0 

8 

48-0 

0-250 

14-0 

11 

154-0 

0-375 

19-0 

13 

247*0 

Copper 

0-500 
0-625 

25-0 
31-0 

16 

18 

400-0 

558-0 

0-750 

36-5 

21 

766-5 

0-875 

43-0 

22 

946-0 

i-ooo 

49-0 

23 

1127-0 

The  Electrical  Times,  in  its  number  of  5th  September,  1907, 
gives  the  following  interesting  particulars  of  applications  of 
Thomson  process : — 

"  A  new  method  of  uniting  the  surfaces  of  metal  plates  has 
recently  been  patented,  in  which  the  Thomson  process  is 


ELECTRIC  WELDING 


115 


employed.  The  process  consists  in  forming  ridges  or  pro- 
jections on  the  surfaces  to  be  joined.  These  projections  set 
up  local  heating,  and  when  the  projections  are  at  the  right 
temperature,  they  are  welded  together  by  pressure.  Fig.  47 
shows  a  number  of  different  ways  of  forming  such  projections 
for  this  purpose. 

i — 


One  of  the  appli- 
cations of  this 
method  lies  in  the 
manufacture  of 
small  pulleys  for 
window  sashes,  etc.  < 
In  these  cases,  the 
pulleys  are  each 
made  of  two  cir- 
cular stampings,  having  a  number  of  projections  formed  on  the 
surfaces  to  be  joined  as  shown  in  Fig.  48.  These  stampings 
are  placed  in  the  welding  machine  in  the  proper  position  and 
welded  in  the  manner  above  described.  The  machine  is 
entirely  automatic,  except  that  the  stampings  are  fed  into 

the  machine  by  the  operator. 
The  work-holder  consists  of  a 
link-belt  working  over  two 
pulleys,  and  moved  forward 
FIG  48  step  by  step  by  the  main  shaft 

of  the  machine.     A  centering 

device  ensures  the  welding  points  coming  opposite  to  each 
other  in  the  work-holder,  and  on  reaching  the  welding  position 
the  electrodes  advance  automatically  and  weld  the  two  stamp- 
ings together,  the  complete  pulley  being  delivered  on  the 
opposite  side  of  the  machine. 

"  Another  patented  method  of  forming  joints  in  thin  material 
is  shown  in  Fig.  49.     The  strips  are  butted  in  the  clamps  of 

i  2 


116 


WELDING  AND   CUTTING  METALS 


r^^~    - 

D 

/n 

--, 

u 

^x^ 

the  welder  in  such  a  way  that  when  heated  and  pressed 
together  the  edges  are  turned  up  against  each  other  as  shown. 
An  automatic  hammer  is  then  used  to  force  the  upturned 
edges  down  against  the  strip,  and  to  press  the  heated  metal 
to  about  the  same  thickness  as  the 
original  strip.  An  extremely  strong 
and  satisfactory  joint  is  the  result.  A 
special  machine  is,  of  course,  used  for 
this  work.  In  this  case  also  the  welder 
is  driven  by  a  pulley,  and  is  automatic 
except  that  the  work  is  placed  in  and 
taken  out  of  the  clamps  by  the  operator. 
The  strip  or  band  being  placed  in  the 
clamps,  is  immediately  gripped  auto- 
matically and  heated  to  the  welding 
temperature.  The  right  hand  plate  is 
then  moved  towards  the  left  by  a  cam, 
turning  up  the  ends  of  the  band  against 
each  other  ;  the  hammer  die  then  falls, 
cutting  off  the  current  and  finishing 
the  joint.  The  clamps  then  open  and 
the  welded  band  is  taken  out ;  the  cycle 
of  operations  is  then  repeated.  From 
350  to  600  welds  are  made  per  hour  on 
this  machine  in  steel  strip  varying  from 
|  in.  to  1J  in.  wide  by  No.  20  to  No.  2 
gauge. 

"  Fig.  50  shows  a  Thomson  electric  welding  machine  specially 
adapted  for  the  manufacture  of  hollow-handled  table  cutlery. 
The  articles  are  made  in  three  parts  as  indicated  in  Fig.  51. 
The  hollow  handle  is  pressed  from  a  sheet  or  disc  and  is 
welded  on  to  one  side  of  a  specially  shaped  bolster.  The 
other  side  of  the  bolster  has  a  projection  so  shaped  as  to 


FIG.  49. 


ELECTBIC  WELDING  117 

present,  approximately,  the  same  cross  section  as  the  blade. 
Two  welds  are  required  to  complete  the  article.  The  machine 
illustrated  is  capable  of  making  from  250  to  300  welds  per 
hour,  and  requires  only  a  boy  to  operate  it.  In  the  case  of 
articles  having  German-silver  handles,  a  steel  ring  is  shrunk 


FIG.  50. 


on  to  the  end,  and  this  is  welded  on  to  the  bolster  in  the 
same  way  as  the  steel  handle.  One  great  advantage  of  this 
method  of  manufacture  is  that  the  welded  joints  prevent  the 


FIG.  51. 

liquid  used  in  plating  from  entering  the  hollow  portion  and 
corroding  the  metal. 

"  An  interesting  product  of  the  Thomson  process  is  electri- 
cally welded  wire  netting.  The  machine  employed  is  entirely 
automatic  and  works  continuously  as  long  as  the  supply  of 
wire  holds  out.  The  wires  corresponding  to  the  horizontal 
wires  in  the  finished  netting  are  fed  into  the  machine  from  a 


118  WELDING  AND  CUTTING  METALS 

number  of  reels  on  the  top,  and  another  reel  is  placed  at  the 
side  from  which  the  lengths  of  wire  forming  the  vertical  wires 
in  the  finished  netting  are  cut  off  automatically  as  the  work 
proceeds.  A  series  of  small  electric  welders,  corresponding  in 
number  to  the  horizontal  wires  in  the  netting,  come  into 
operation  automatically  and  weld  the  joints  together  where 
the  wires  cross.  The  welded  netting  then  moves  forward  a 
given  distance  and  the  work  is  repeated.  A  single  machine 
turns  out,  in  this  way,  complete  rolls  of  wire  fencing  of  any 
desired  length.  No  twists  or  loops  are  made  in  the  wire,  and 
there  is  thus  a  saving  in  material ;  the  joints  are  also  much 
stronger  than  any  form  of  twist. 

"  Another  mode  of  manufacture  is  employed  in  the  case  of 


EIG.  52. 

the  crankshaft  of  an  automobile  engine  which  is  built  up  by 
welding  the  several  parts  together.  The  two  central  portions 
are  drop  forgings,  while  the  other  two  consist  of  drawn  steel 
shaped  to  about  the  finished  size.  By  means  of  a  suitable 
welding  machine,  the  parts  are  guided  together  and  united 
with  great  accuracy. 

"  It  may  be  said  that  practically  a  new  industry  has  arisen 
in  the  making  of  square  and  hexagon  headed  bolts  by  electric 
welding.  For  the  heads,  specially  die-drawn  stock  of  the 
required  shape  is  used,  the  stock  being  drawn  very  accurately 
with  a  variation  not  exceeding  0'003  in.  The  heads  are  cut 
from  the  bar  by  automatic  machines  which  turn  a  projection 
or  shoulder  to  the  diameter  of  the  bolt  to  be  welded  as  shown 
in  Fig.  52.  The  bolt,  drawn  from  high  grade  round  stock  of 
the  finished  diameter,  is  then  electrically  welded  to  the 


ELECTEIC  WELDIXG  119 

projection  on  a  specially  designed  welder  fitted  with  hydraulic 
upsetting  device.  The  burr  is  then  milled  off,  and  at  the 
same  time  the  top  of  the  head  is  shaped,  the  under  part  of  the 
head  is  formed,  and  the  end  pointed.  In  this  way  absolute 
uniformity  in  length  of  bolt,  height  of  head,  and  alignment  of 
head  and  body  are  obtained.  It  then  only  remains  to  cut  the 
thread.  The  latter  being  cut  on  the  surface  of  the  die-drawn 
stock  the  tensile  strength  of  the  bolts  is  greater  than  that  of 
milled  or  upset  bolts.  Special  adaptations  of  the  method 
include  bolts  of  soft  die-drawn  stock  with  case-hardened 
heads,  and  steel  bolts  with  brass  heads,  the  latter  being 
used  largely  by  switchboard  makers.  A  large  factory  has 
been  established  employing  no  less  than  400  h.p.  devoted 
exclusively  to  the  manufacture  of  these  electrically  welded 
bolts. 

"  The  Thomson  patent  chain  welder  is  provided  with  an 
automatic  hammer  driven  by  a  belt,  which  practically  removes 
the  burr  caused  by  pressing  the  heated  ends  of  the  link 
together,  leaving  only  a  fin  of  metal  which  is  easily  shaken 
off  by  rumbling  for  a  few  minutes  in  the  usual  way.  The 
link  to  be  welded  is  held  in  a  specially  shaped  die,  and  current 
is  fed  to  this  link  by  a  pair  of  copper  contacts  mounted  on 
slides  which  are  made  to  engage  the  link  by  means  of  a  foot 
lever.  As  soon  as  the  welding  temperature  is  reached,  the 
hand  lever  on  the  right  hand  side  of  the  machine  is  operated 
to  upset  the  metal  at  the  joint,  and  the  automatic  hammer  is 
set  in  motion  by  a  second  hand  lever  on  the  left  hand  side  of 
the  welder.  The  current-carrying  parts  of  the  slides  are 
water  cooled.  This  machine  is  capable  of  welding  about  300 
links  per  hour  made  of  i  in.  diameter  steel  rod  and  is  suit- 
able for  links  up  to  2J  in.  long  by  1J  in.  wide.  The 
welder  may  be  used  for  either  welding  the  links  separately  or 
in  the  form  of  a  chain ;  in  the  latter  case,  every  other  link  is 


120  WELDING  AND  CUTTING  METALS 

welded,  and  then  the  chain  is  passed  through  the  machine  a 
second  time. 

"Welders  for  harness  rings  and  similar  articles  make  as 
many  as  800  welds  per  hour,  the  rings  being  previously 
formed  to  circular  shape  with  their  ends  cut  off  square  and 
butted  together  ready  for  welding.  Such  machines  have  two 
transformers  and  an  automatic  feeding  device,  the  boy  simply 


FIG.  53. 

inserting  the  rings  in  the  dies,  from  which  they  are  removed 
automatically  after  being  welded. 

"  Fig.  53  shows  a  new  design  of  machine  for  welding  the 
smallest  sizes  of  iron,  brass,  German-silver,  copper,  and  other 
wires  in  which  it  is  essential  that  the  action  of  the  machine 
should  be  as  nearly  as  possible  automatic,  and  the  mechanism 
so  designed  as  to  have  the  least  amount  of  friction.  One 
feature  of  this  machine  is  a  special  arrangement  to  enable 
the  welding  operation  to  be  safely  and  easily  conducted  by 
persons  having  little  or  no  knowledge  of  the  mechanical  or 
electrical  conditions  necessary  to  produce  good  work.  This 
consists  in  combining  the  automatic  cut-off  devices  which, 


ELECTEIC  WELDING  121 

when  the  weld  is  completed,  automatically  stop  the  flow  of 
current  through  the  work,  with  the  starting  switch.  Tims 
the  cut-off  can  only  be  re-set  by  restoring  the  starting  switch 
to  the  '  off '  position.  This  is  accomplished  by  a  push-rod 
which  projects  through  the  front  of  the  case,  and  which  closes 
the  starting  switch.  A  latch  is  fitted  to  the  rod  which 
engages  with  the  cat-off  device  in-  such  a  manner  that  no 
current  can  flow  through  the  primary  of  the  transformer  until 
the  automatic  cut-off  has  been  re-set.  Another  feature  of  the 
welder  is  that  the  movable  clamp  which  presses  the  ends  of 
the  wire  together  when  the  right  temperature  is  attained, 
runs  on  roller  bearings,  and  the  connection  between  the 
clamp  and  the  transformer  secondary  is  made  by  a  projection 
on  the  underside  dipping  into  a  mercury  bath  formed  in  the 
top  of  the  secondary.  A  reactive  coil  for  controlling  the  heat 
to  suit  any  particular  size  or  quality  of  wire  is  mounted  on 
the  frame  of  the  welder,  and  is  furnished  with  two  windings. 
A  two-way  switch,  operated  by  a  sliding  rod  on  the  front  of 
the  case,  connects  these  windings  in  series  or  parallel,  thus 
giving  a  considerable  range  of  control,  and  ensuring  satisfactory 
welds  in  the  smaller  gauges  of  wire. 

"  Figs.  54,  55  illustrate  some  articles  welded  by  the  Thomson 
process. 

"  Central  station  engineers  have  hitherto  been  somewhat 
chary  in  connecting  electric  welders  of  large  size  to  their 
mains  on  account  of  the  fluctuating  nature  of  the  load,  although 
there  are  numerous  instances  of  small  welders  being  so  used. 
A  very  interesting  installation  has  recently  been  completed  in 
London  by  the  Electric  Welding  Company,  Limited,  in  which  a 
welder  of  90  kw.  capacity  is  worked  off  a  single-phase  power 
supply  at  400  volts.  In  order  to  prevent  undue  fluctuations  of 
voltage  on  the  mains,  a  special  substitutional  resistance  is 
installed,  built  in  three  sections,  each,  controlled  by  a  switch,  so 


122  WELDING  AND  CUTTING  METALS 

that  one  or  more  sections  can  be  put  in  circuit  according  to  the 
size  of  the  work  being  welded.  A  large  liquid  resistance  is 
also  employed  to  prevent  an  undue  rush  of  current  when  the 
primary  circuit  of  the  welding  transformer  is  closed,  the 
plates  being  raised  and  lowered  by  a  small  motor  through 
suitable  gearing.  The  controlling  switch  of  the  welder  is  so 


FIG.  54. — Pipe  Coil  for  Befrigerating  Machine,  Electrically  Welded  by  Thomson 
Process.  Pipes  Welded  end  to  end  by  moving  Welding  Machine  during 
Operation  of  Coiling. 

arranged  that  when  put  in  the  '  on  '  position  it  starts  the 
plate-lowering  gear,  thus  gradually  cutting  out  the  starting 
resistance,  and  vice  versa.  This  plant  is  in  continuous 
operation,  and  no  inconvenience  to  other  power  users 
in  the  neighbourhood  has  been  reported.  Another  welder 
of  smaller  size  has  also  been  connected  to  this  circuit.  In 
this  case  a  special  economy  coil  is  used  as  a  regulating 
device. 


ELECTRIC  WELDING 


123 


124  WELDING  AND   CUTTING  METALS 

"  To  facilitate  the  working  of  electric  welding  machines  on 
polyphase  circuits,  Professor  Elihu  Thomson  has  recently 
patented  a  method  of  winding  the  transformers  to  prevent 
unbalancing  the  phases.  This  will  doubtless  lead  to  consider- 
able developments  in  the  near  future,  seeing  that  the  power 
companies'  supply  mains  are  available  in  most  manufacturing 
centres." 

Electric  welding  has  been  in  constant  operation,  for  many 
years,  at  the  works  of  Messrs.  Stewarts  and  Lloyds,  Limited, 
and  has  chiefly  been  employed  on  large  pipes  and  fittings 
for  high-pressure  steam. 

The  weld  is  absolutely  solid,  and  exhaustive  tests  have 
proved  it  to  be  equally  as  strong  as  the  tube  itself. 

When  it  was  proposed  a  few  years  ago  (owing  to  the 
increasing  steam  pressures  and  temperatures  causing  trouble 
with  the  copper  and  cast-iron  pipes  then  in  use)  to  adopt 
wrought-iron  or  steel  piping  for  steam-pipe  installations, 
great  difficulty  was  experienced  in  obtaining  a  thoroughly 
satisfactory  form  of  flange  joint  for  the  wrought  piping ; 
and  it  was  not  until  the  introduction  by  Stewarts  and 
Lloyds,  Limited,  of  their  flanges  welded  solid  to  the  pipe, 
that  the  use  of  wrought-iron  and  steel  steam-pipes  became 
general. 

At  first  the  flanges  were  welded  on  to  the  pipe  plain ; 
but  subsequently  the  firm  instituted  an  improvement  by  per- 
fecting a  machine  which  leaves  a  large  fillet  at  the  root  of  the 
fiange.  This  fillet,  which  gradually  reduces  the  thickness  of 
the  metal  from  flange  to  pipe,  enables  both  to  be  brought  to 
a,  welding  heat  and  to  be  perfectly  welded  without  overheating. 
This  operation  cannot  be  satisfactorily  performed  with  plain 
flanges,  nor  with  those  formed  with  a  large  boss  at  back. 
The  improved  method  ensures  a  sound  weld  over  the 
whole  area  of  contact,  which,  in  consequence  of  the  fillet, 


ELECTEIC  WELDING  125 

is  about  twice  as  great  as  it  was  before  the  improvement 
was  introduced. 

This  fillet  also  gives  greater  stiffness  to  the  flange  and 
makes  the  joint  thoroughly  reliable  for  the  highest  pressures. 
It  also  enables  larger  size  pipes  and  higher  pressures  to  be 
used  for  hydraulic  purposes  than  formerly. 

These  welded-on  flanges  are  now  being  specified  by  consult- 
ing engineers  and  steam  users  generally  for  all  high-class 


FIG.  56. — Form  of  Special  Facing  for  Electrically 
Welded  Flanges  :  Plain  Faced. 

work  ;  and  the  prices,  as  a  rule,  compare  favourably  with 
those  for  inferior  types  of  joints. 

Pipes  with  these  flanges  have  repeatedly  been  tested  to 
destruction,  and  special  tests  have  been  made  to  satisfy  the 
rigid  requirements  of  the  Board  of  Trade,  and  also  of  the 
Engineering  Standards  Committee. 

As  a  result,  it  has  been  found  that  pipes  of  the  thicknesses 
specified  in  the  table  given  below  for  200  Ibs.  steam  working 
pressure  (which  carry  a  factor  of  safety  of  nine  and  over) 
invariably  burst  before  the  flanges  show  any  signs  of  fatigue. 
Destruction  tests  have,  in  all  eases. j  T  proved  the  flanges  to 


126  WELDIXG  AXD   CUTTING  METALS 

PIGS.  56  to  59.— Forms  of  Special  Facing  for  Electrically  Welded  Flanges. 


FIG.  57. — Single  Spigot  and  Faucet. 


FIG.  58. — Double  Spigot  and  Faucet. 


FIG.  59.— Facing  Strips. 


ELECTEIC  WELDING  127 

be  thoroughly  welded  on  to  the  pipe ;  and  under  mechanical 
tests,  the  flanges  and  pipes  bent  and  finally  broke,  while  the 
continuity  of  the  weld  remained  undisturbed. 

.The  tests  under  the  Board  of  Trade  requirements  were  made 
to  the  direction  of  their  inspectors,  who,  after  witnessing  the 
various  operations,  and  having  satisfied  themselves  that  the 
bursting  tests  of  the  pipe  would  not  disclose  any  defect  in 
the  flange  welds,  proceeded  to  demolish  a  number  of  the 
flanged  pipes  under  steam  hammers. 

The  flanged  pipes  were  divided  longitudinally  into  four 
pieces,  and  bent  cold  to  the  various  shapes,  the  object  being 
to  subject  the  metal  in  the  neighbourhood  of  the  welds  to 
the  greatest  possible  strain,  and  in  no  case  was  the  weld 
in  any  way  disturbed. 

The  result  of  these  tests  was  the  acceptance  of  pipes  with 
welded-on  flanges  for  any  work  under  Board  of  Trade 
survey. 

The  flanges  are  generally  made  from  wrought-iron,  and  all 
facing,  edging  and  drilling  is  done  on  up-to-date  machines, 
and  the  greatest  care  exercised  to  ensure  a  high  standard  of 
accuracy. 

The  joints  are,  as  a  rule,  faced  plain,  as  Fig.  56.  If 
required,  the  flanges  can  be  faced  either  with  a  single  or 
double  spigot  and  faucet,  as  Figs.  57  and  58,  or  with  a 
double  spigot  as  Fig.  59,  all  of  which  types  of  facing  are 
frequently  used  in  connection  with  high -pressure  steam- 
pipes,  and  are  eminently  suitable  for  use  with  metal  joint 
rings. 

Wrought  fittings  of  all  kinds  for  steam  and  other  pipe 
installations,  such  as  bends,  branch  pipes,  expansion  bends, 
etc.,  can  be  fitted  with  electrically  welded-on  flanges,  and 
a  few  specialities  in  this  direction  will  be  found  illustrated 
below. 


128 


WELDING  AND   CUTTING  METALS 


DIMENSIONS  OF  PIPES  AND  FLANGES. 

For  steam  pressures  up  to  200  Ibs.  per  square  inch,  as  also 
the  minimum  thickness  recommended  for  lap-welded  steel 
pipes  for  that  pressure  : — 


Bore  of 
Pipe. 

External 
Diam.  of 
Pipe. 

Thickness 
of  Pipe. 

Diam.  of 
Flange. 

Thick- 
ness of 
Flange. 

Diam.  of 
Bolt 
Circle. 

Number 
of  Bolts. 

Size  of 
Bolts. 

Ins. 

Ins. 

Ins. 

Ins. 

Ins. 

Ins. 

1 

1A 

7  W.G. 

42 

1 

3J 

4 

J 

11 

If 

6      „ 

5J 

T% 

4 

4 

i 

2 

2f 

5      ,, 

6 

1 

4f 

6 

21 

3 

5      „ 

7 

1 

5j 

6 

1 

3 

Si 

i  in. 

7^ 

J 

6 

6 

f 

3J 

4 

i   » 

8 

f 

6J 

6 

I 

4 

4J 

4     " 

9 

7| 

6 

i 

5 

6* 

i  ,, 

10 

7 
f 

81 

6 

i 

6 

6J 

i  ,, 

11 

1 

91 

8 

i 

7 

¥    » 

12 

1 

lOf 

8 

| 

8 

&i 

i  „ 

13 

1 

Hf 

8 

9 

91 

15 

IB 

13 

8 

7 

¥ 

10 

lOf 

5 
T6      » 

17 

IF 

14f 

10 

J 

11 

11* 

18 

i*- 

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10 

7 

8" 

12 

12* 

A  »» 

19 

14 

16f 

12 

1 

13 

13f 

A  ^ 

20 

lit 

17f 

12 

1 

14 

14| 

t%  " 

21 

ij 

18J 

12 

1 

15 

15| 

f  „ 

22 

li 

19f 

16 

1 

16 

f  „ 

23 

li 

20| 

16 

1 

17 

17J 

f  „ 

24 

li 

2  If 

16 

1 

18 

18|; 

§  ,. 

25 

If 

22f 

20 

1 

19 

19^ 

f  ,. 

26J 

If 

24 

20 

1 

20 

20|^ 

§  „ 

27j 

If 

25^ 

20 

11 

21 

21| 

A    r, 

29 

If 

26| 

20 

H 

22 

22J 

TF    " 

30J 

1* 

27| 

20 

23 

23| 

T(T    >» 

31£ 

28| 

20 

l| 

24 

24J 

A  » 

32J 

4 

29f 

20 

it 

Figs.  60  to  64  are  some  illustrations  of  the  firm's  electrically 
\velded-on  branches,  drain  pockets  and  bosses. 


ELECTEIC  WELDING 


129 


These  are  usually  welded  on  to  long  lengths  of  pipe,  and  con- 
sequently the  number  of  flange  joints  in  a  range  of  pipes,  which 
would  be  necessary  if  short  fittings  were  used,  is  materially 
reduced. 


FIG.  60.— Branch  and  Boss  on  Centre  Line  of  Pipe. 


PIG.  61. — Branch  on  Centre          FIG.  62.— Branch  off  Centre 
Line  of  Pipe.  Line  of  Pipe. 


FIG.  63.— Drain  Pocket.  FIG.  64.— Drain  Pocket  in  Section. 

FIGS.  60  to  64.— Various  Forms  of  Electrically  Welded  Branch,  etc. 

The  most  general  forms  of  branch  are  those  on  centre  line  of 
pipe  (Fig.  61),  and  those  off  centre  line  of  pipe  (Fig.  62),  but 
the  firm  make  a  speciality  of  curved  branches,  which  are  in 
favour  with  some  engineers. 

Several  branches  can  be  welded  on  to  one  length  of  pipe  or 
bend. 

Drain  pockets  (Figs.  63  and  64),  with  end  welded  in,  and 
tapped  to  connect  to  drain  piping,  can  be  welded  on  to  long 


130 


WELDING  AND  CUTTING  METALS 


lengths  of  steam  piping  in  any  position,  and  are  a  valuable 
adjunct  to  a  steam  installation,  as  they  dispense  with  super- 

k A >|< A 


i 
FIG.  68.—"  Y  "  Piece.  FIG.  69.— Breeches  Piece. 

FIGS.  65  to  69.— Wrought  Steel  Fittings,  Electrically  Welded. 

fluous  flange  joints,  and  are  considerably  stronger  and  cheaper 
than  any  other  form  of  pocket.  They  are  usually  welded  on 
to  the  main  pipe  directly  under  the  branches  to  the  engines. 


ELECTEIC  WELDING 


131 


Bosses  for  drain  piping,  steam  gauges,  thermometers,  etc. 
are  welded  on  pipes,  faced,  and  tapped  to  requirements. 

One  distinct  advantage  peculiar  to  the  electric  welding 
process — as  regards  wrought  fittings — is  the  ability  to  meet 
the  long-desired  want  of  the  engineer  who,  having  to  contend 
with  high  pressures,  is  restricted  by  a  very  limited  space  at 
his  disposal.  With  the  assistance  of  the  electric  welding 
wrought-steel  tees,  crosses,  "  Y  "  pieces,  bends,  and  breeches 
pieces — all  fitted  with  welded  flanges — can  be  supplied  of 
shorter  dimensions  than  can  be  made  by  any  other  process. 

Figs.  65  to  69  and  the  following  table,  giving  the  minimum 
dimensions  for  each  size  up  to  36  ins.  diameter  of  the  above 
fittings,  will  no  doubt  be  of  interest  as  indicating  what  may 
now  be  supplied  for  restricted  positions. 

MINIMUM  DIMENSIONS. 


Bore. 

A 

B 

c 

D 

Bore. 

A 

B 

c 

D 

Ins. 

Ins. 

Ins. 

Ins. 

Ins. 

Ins. 

Ins. 

Ins. 

Ins.. 

Ins. 

1 

3* 

3| 

2f 

6 

18 

15* 

25 

7 

29 

2 

4* 

8J 

7* 

19 

16* 

26 

7 

30* 

2* 

5 

64 

34 

8* 

20 

17 

27^ 

7* 

31* 

3 

5* 

7 

4 

9* 

21 

18 

28| 

7f 

33 

31 

6 

74 

4J 

22 

19 

30 

8 

35 

4 

6* 

B| 

44 

II4 

23 

19* 

31 

8 

36 

5 

7^ 

12 

24 

20 

32 

8 

37 

6 

8 

11¥ 

5 

13 

25 

21 

331 

Ql 

39 

7 

si 

12* 

54 

14* 

26 

22 

34| 

8* 

40 

8 

9 

13* 

§ 

16 

27 

23 

36 

9 

41 

9 

10 

144 

18 

28 

24 

37 

9 

42 

10 

11 

16 

6* 

20 

29 

25 

38 

9 

43 

11 

11* 

17J 

6J 

21 

30 

26 

39* 

9J 

44 

12 

18J 

22 

31 

27 

40^ 

9* 

46 

13 

132 

19t 

6J 

23 

32 

28 

42 

10 

47 

14 

13* 

64 

25 

33 

29 

43 

10 

48 

15 

14 

21-| 

6| 

26 

34 

30 

441 

10* 

49 

16 

14* 

22f 

6| 

27 

35 

31 

45* 

50 

17 

15 

2SJ 

6| 

28 

36 

32 

47 

II2 

51 

K   2 


132 


WELDING  AND  CUTTING  METALS 


FIG.  70. — Elevation. 


.  7i._ End  View. 

FIGS.  70  to  71.— Wrought 

Steel  Steam  Eeceiver.  FIG.  74.—"  Horseshoe     Type. 

FIGS.  70  to  74.— Eeceiver  and  Bends,  Electrically  Welded. 


ELECTEIC  WELDING 


133 


Four  receivers  (Figs.  70,  71)  were  made  by  Messrs.  Stewarts 
and  Lloyds,  Limited,  recently,  for  the  Birmingham  Summer 
Lane  electric  power  station.  They  were  11  ft.  long,  and  were 
manufactured  from  30  ins.  bore  by  1  in.  thick  wrought-steel 
lap-welded  tube  with  ends  swaged  down  and  all  branches  and 
flanges  electrically  welded  on. 

The  receivers  were  tested  by  hydraulic  pressure  to  500  Ibs. 
per  square  inch. 

DIMENSIONS  OF  STANDAED  BENDS. 
For  full  particulars  of  flanges,  see  page  124. 


Bore. 

Centre 
to  Face. 
A 

Radius. 
B 

Straight 
at  Ends. 
C 

Diameter 
of  Flange. 
D 

Ins. 

Ft. 

Ins. 

Ft. 

Ins. 

Ft. 

Ins. 

Ins. 

1 

0 

6                  0 

3 

0 

3 

4 

1^ 

0 

71               0 

41 

0 

3 

2^ 

0 

91 

0 

6 

0 

31 

62 

2J 

0 

Hi 

0 

71 

0 

4 

7 

3 

1 

11 

0 

9 

0 

4J 

71 

31 

1 

3 

0 

101 

0 

41 

8 

4 

1 

5 

1 

0 

0 

5 

9 

5 

1 

9 

1 

3 

0 

6 

10 

6 

2 

1 

1 

6 

0 

7 

11 

7 

2 

4 

1 

9 

0 

7 

12 

8 

2 

11 

2 

3 

0 

8 

13 

9 

3 

2 

2 

6 

0 

8 

15 

10 

3 

9 

3 

0 

0 

9 

17 

11 

4 

3 

3 

6 

0 

9 

18 

12 

4 

10 

4 

0 

0 

10                19 

13 

5 

5 

4 

6 

0 

11 

20 

14 

6 

3 

5 

3 

1 

0 

21 

15 

6 

10 

5 

9 

1 

1 

22 

16 

7 

8 

6 

6 

1 

2 

23 

17 

8 

3 

7 

0 

1 

3                24 

18                8 

9 

7 

6 

1 

3                25 

Bends  over  18   ins.    are   generally   manufactured    by   the 
electrical  process. 


134 


WELDING  AND  CUTTING  METALS 


The   above   bends    are   manufactured   from   wrought  steel 
lap-welded  pipe  and  are  fitted  with  welded  flanges. 

DIMENSIONS  OF  STANDARD  "HORSESHOE"  EXPANSION  BENDS. 


Bore. 

Face  to  Face. 
A 

Centre 
to  Centre. 
B 

Centre 
to  Centre. 
C 

Diameter 
of  Flanges. 

Ins. 

Ins. 

Ins. 

Ins. 

Ins. 

1 

18 

18 

9 

4£ 

i| 

21 

21 

10J 

4 

2 

24 

24 

12 

6 

&i 

27 

28 

14 

7 

3 

30 

30 

15 

7J 

3J 

35 

34 

17 

8 

4 

40 

39 

18 

9 

5 

50 

48 

24 

10 

6 

58 

60 

30 

11 

7 

64 

72 

36 

12 

8 

72 

84 

42 

13 

Above  bends  are  made  from  lap-welded  steel  pipe,  and  are 
fitted  with  welded-on  flanges. 

The  illustrations  (Figs.  77,  78,  page  136)  show  a  24  in. 
"  compound  "  expansion  arrangement  with  12  in.  connecting 
bends. 

"  Compound "  expansion  arrangements,  as  shown  above, 
are  manufactured  from  wrought  steel  lap-welded  pipe. 

The  branches  on  the  headers  are  electrically  welded  into 
place,  and  all  flanges  are  solidly  welded  on. 

The  standard  types  of  sliding  expansion  joints  are  illustrated 
in  Figs.  79  and  80,  page  136. 

These  are  solidly  welded,  of  wrought  steel  throughout,  and 
have  the  branches  and  internal  baffle  plate  electrically  welded 
into  position. 

Bosses  for  water  gauge  fittings  are  welded  on  when  required. 


ELECTRIC   WELDING  135 

The  joints  of  rails  have  principally  been  welded  by  "  Thermit " 
as  mentioned  on  page  70,  but  it  may  also  be  done  by  electrical 
means.  An  electrically  welded  joint  is  made  by  welding  steel 
blocks  to  the  rail  end.  A  steel  block  is  placed  on  each  side  of 
the  rail  at  the  joint,  and  a  heavy 
current  is  passed  through  from  one 
block  to  the  other.  This  current 
is  so  great  that  the  electrical  resist- 
ance between  the  rail  and  steel  block 
causes  that  point  to  become  molten. 
Current  is  then  shut  off,  and  the 
joint  allowed  to  cool.  There  is  in 
this  case  a  true  weld  between  the 
steel  blocks  and  the  rails. 

An  electric  welding  outfit  being 
expensive  to  maintain  and  operate,     FlG-  15'~C^n^  Expansion 
this  process  is  used  only  where  a 

large  amount  of  welding  can  be  done  at  once.  Current  is 
taken  from  the  trolley  wire,  a  rotary  converter  set  takes 

500  volt  direct   current  from 

jjjfply^  the  trolley  wire,  and  converts 

^m      ^^ibk  w^f     ^    *n^°    a^erna^mg    current. 

^^^^  This    alternating    current    is 

^^^^  taken  to  a  static  transformer, 

^^^^^W      which  reduces  the  voltage  and 

gives  a   high   current  at  low 

,,  .  a  „ ,.,  TJ     ,      voltage,     the     latter     current 

EIG.  76. — "  8     Expansion  Bend. 

being     passed     through    the 

blocks  and  rails  in  the  welding  process.  A  massive  pair  of 
clamps  is  used  to  hold  the  blocks  against  the  rails,  and  to 
conduct  the  current  to  and  from  the  joint  while  it  is  being 
welded.  These  clamps  are  water  cooled  by  having  water 
circulated  through  them  so  that  they  will  not  become  over- 
heated at  the  point  of  contact  with  the  steel  blocks. 


136 


WELDING  AND  CUTTING  METALS 


Cost  of  Electric  Welding. — A  few  examples  giving  actual 
figures  may  be  of  interest. 

(a)  Ordinary  Articles. — The  cost  of  an  universal  machine 
for  electric  welding,  size  3,  for  sections  up  to  3,000  mm. 


FIG.  78. 


PIG.  77. 


FIG.  79. 


FIG.  80. 


FIGS.  77  to  80. — Compound  and  Sliding  Expansion  Joints,  Electrically 

Welded. 

(about  45  square  inches),  is  about  £170 ;  add  to  this  15  pel- 
cent,  for  interest  and  depreciation,  equal  to  £25  10s.,  or  an 
expense  of  Is.  Id.  per  working  day.  With  this  machine 
three  welds  of  maximum  section  can  be  made  in  two  minutes 


ELECTRIC  WELDING  137 

(fifty  seconds  of  which  being  actually  absorbed  by  the  welding 
alone),  making  900  welds  every  ten  hours,  requiring  roughly 
125  h.p.  hours  or  75  kilowatt-hours,  or  about  7s.  6d.  for 
electric  energy,  and  with  a  man  at  4s.  a  day,  a  total  cost 
for  900  welds  would  be  13s.  Id. 

Assume  that  two  men  can  make,  in  average,  by  fire,  one 
weld  in  two  minutes,  or  300  welds  per  day,  it  would  take  them 
three  days  to  make  the  900  welds,  earning  thereby  24s. ;  add 
to  this  1*5  cwt.  of  coal  at  Is.  6d.  per  day  =  6s.  9d.,  and  Is.  for 


FIG.  81.— Steam  Dryer,  Electrically  Welded. 

tools,  making  a  total  cost  of  31s.  9d.,  or  a  difference  of  18s.  Sd. 
in  favour  of  electric  welding. 

The  above  figures  refer  to  welding  of  ordinary  articles,  but 
the  advantages  of  electric  welding  are  still  more  prominent 
in  complicated  articles,  the  handling  of  which  is  difficult,  if 
not  impossible,  for  welding  by  fire. 

(b)  Water-pipes. — An  able  smith  with  two  assistants  can  in 
the  best  case  weld  fifty  ordinary  water-pipes  a  day ;  the  same 
man  can  easily  with  an  electric  welding  machine  make  300 
such  welds  per  day. 

(c)  Chain  Welding. — A  skilled   chain-smith    can  weld  two 
links  per  minute.     At  Jserlohn  one  man  welds  with  an  electric 
chain  machine  seventeen  links  per  minute,  or  eight  times  as 
much  as  the  chain-smith. 


138  WELDING  AND   CUTTING  METALS 

The  great  saving  of  cost  in  management,  time  and  labour ; 
the  easy  and  often  automatic  manipulation  of  the  machines, 
which  do  not  require  skilled  labour  ;  the  cleanliness,  there 
being  no  dust  or  smoke  from  fire;  and  the  absolute  freedom  from 
danger,  there  being  only  secondary  currents  of  low  tension  ; 
and,  in  addition  thereto,  special  machines  for  almost  any  con- 
ceivable article,  offer  to  electric  welding  advantages  of  far 
greater  extension  and  importance  than  those  obtainable  by 
any  other  welding  system. 


THE  FORGING  PROCESS. 

By  the  forging  process  the  parts  to  be  united  are  heated  to 
a,  temperature  considerably  less  than  that  of  fusion. 

It  is  sufficient  to  put  into  contact  the  two  metals  brought 
to  white  heat  and  hammer  them  together.  The  hammering 
may  be  substituted  for  pressing  or  rolling,  but  these  means 
are  inferior,  as  it  cannot  produce  a  proper  weld. 

The  weld  by  forging  has  some  disadvantages.  The  tempera- 
ture which  is  required  easily  causes  the  iron  to  oxidise  ;  the 
presence  of  oxide  of  iron  offers  great  resistance  to  the  welding 
and  renders  difficulty  for  the  metals  to  join  with  one  another ; 
during  the  operation  of  the  welding,  which  ought  to  be  done 
in  the  open  air,  the  oxidation  cannot  be  prevented.  The 
welder,  in  order  to  minimise  the  oxidation,  employs  some 
sand  or  borax,  but  in  both  cases  a  silicate  is  formed,  which  is 
very  fusible  and  must  be  removed  by  the  hammering. 

The  inconvenience  of  the  oxidation  makes  the  forging 
unsuitable  for  articles  of  small  and  thin  dimensions,  such  as 
tools,  wires,  etc.,  because  the  oxidation  being  too  rapid,  the 
metal  burns  but  does  not  weld. 

The  necessity  of  hammering  makes  it  also  difficult  to  apply 
forging  to  various  objects  by  reason  of  their  form  or  the 


HYDKOGEN  WELDING  139 

difficulty  of   their  removal ;  for   instance,  tubes,  cisterns,  or 
objects  of  a  voluminous  form. 

It  is  in  such  cases,  where  the  forge  is  insufficient,  or  the 
•application  difficult,  that  the  welding  by  fusion  is  resorted  to. 

HYDROGEN  WELDING. 

The  application  of  hydrogen  to  welding  was  introduced  a 
few  years  since  by  L'Oxhydrique  Internationale,  Societe 
Anonyme,  Brussels. 

To  effect  a  satisfactory  hydrogen  weld  it  is  necessary  to 
obtain  not  only  a  complete  absorption  of  the  oxygen  by  the 
hydrogen,  but  also  an  absolutely  homogeneous  flame. 

At  first  it  was  suggested  to  obtain  this  by  means  of  a  blow- 
pipe. The  fear  of  an  explosion  taking  place  prevented, 
however,  for  a  long  time,  to  carry  this  suggestion  into  effect. 
It  was  found  advisable  to  mix  the  two  gases  before  the  inflam- 
mation, for  which  purpose  they  were  separately  conveyed  in 
parallel  or  slightly  converging  tubes  to  the  burner.  It  is  easily 
understood  what  an  unsatisfactory  flame  would  thereby  be 
obtained. 

The  proposal  by  L'Oxhydrique,  in  1901,  to  mix  the  two 
gases  in  the  body  of  the  blowpipe  aroused  considerable 
interest,  as  it  really  created  the  autogenous  welding,  soon 
followed  by  substituting  the  hydrogen  with  acetylene  or  other 
suitable  combustible  gases. 

The  gas  of  combustion  is  always  oxygen,  which  may  be 
obtained  direct  from  the  atmosphere,  in  which  case  it  remains 
mixed  with  nitrogen,  while  the  combustible  gas  is  hydrogen, 
or  acetylene,  coal  gas,  and  the  like. 

The  molecules  of  the  oxygen  and  the  combustible  hydrogen 
arrive  at  the  flame  entirely  mixed  in  the  proportions  desired 
to  produce  a  perfect  combustion,  for  which  purpose  is 


140  WELDING  AND  CUTTING  METALS 

required  one  volume  of  oxygen  to  four  or  six  volumes  of 
hydrogen. 

But  a  certain  mixture  of  hydrogen  and  oxygen  forms  an 
explosive  gas,  which  must  as  far  as  possible  be  prevented. 
This  is  easily  done  by  giving  the  mixture  of  gas  a  velocity 
superior  to  the  rapidity  of  the  spreading  of  the  flame.  It  is 
well  known  that  the  total  mass  of  a  mixture  of  explosive  gas, 
contained  in  a  tube,  does  not  ignite  instantaneously.  If  com- 
bustion is  caused  at  one  of  the  extremities  of  the  tube,  the 
burning  of  the  mass  spreads  with  a  certain  velocity,  increasing 
as  the  square  of  the  section  of  the  tube.  If,  therefore,  the 
gaseous  mixture  appears  towards  the  point  of  ignition  with  a 
greater  velocity  than  the  propagation  of  the  flame,  then  the 
fire  does  not  reach  the  inner  part  of  the  tube.  This  may,  no 
doubt,  seem  a  simple  discovery,  nevertheless  it  is  worth 
consideration. 

It  happens  sometimes,  however,  that  the  velocity  of  the 
current  decreases  by  reason  of  some  momentary  incident ;  for 
instance,  if  the  welder  brings  the  burner  of  the  blowpipe  too 
close  to  the  weld,  if  it  is  brought  into  contact  with  the  rubber 
tubes,  or  if  the  pressure  regulator  does  not  act.  The  result 
will  be  an  interior  combustion.  It  is  an  incident  like  those 
which  always  will  happen,  but  of  no  importance  or  danger 
whatsoever,  causing  an  interruption  in  the  work  for  less  than 
two  seconds,  as  the  flame  reignites  immediately  by  itself. 

In  order  to  avoid  this  small  annoyance  a  special  mixing 
apparatus,  M  (Fig.  82),  is  employed.  It  consists  of  a  chamber 
filled  with  water  to  maintain  a  low  temperature,  or  any 
other  suitable  material  able  rapidly  to  absorb  the  heat, 
and  a  finely-drawn  metal  spiral.  The  mixture  of  the  gases 
takes  place  in  the  spiral  in  the  same  manner  as  in  the 
blowpipe,  becoming  warmer  and  warmer.  The  surface  as 
well  as  the  diameter  of  the  spiral  must  be  calculated,  so 


HYDKOGEN   WELDING 


141 


that  in  the  event  of  an  explosion  taking  place  in  the 
interior  the  flame  should  instantly  be  extinguished  by 
the  exterior  colder  temperature.  Furthermore,  to  increase 
the  safety  in  the  case  of  the  flame  not  being  put  out,  the 
volume  of  the  spiral  is  such  as  to  prevent  the  gases  passing 
out  from  the  mixing  chamber  completely  burning,  to  reach 
either  the  blowpipe  or  the  rubber  tube  connecting  the  mixer 
with  the  blowpipe.  In  the  case  of  an  explosion  taking  place, 
the  combustion  ceases  immediately,  the  flame  is  extinguished, 


FIG.  82. 

the  gases  produced  escape,  the  combustible  gases  revive 
instantly,  and  the  flame  is  ignited  by  itself.  Fig.  82  illustrates 
a  complete  oxy-hydrogen  welding  plant. 

The  blowpipe  introduced  by  L'Oxhydrique  under  the  name 
of  Pyrox,  and  patented  in  almost  every  civilised  country,  has 
during  its  existence  of  five  years  proved  to  be  entirely  satis- 
factory in  its  action,  no  accident  whatever  having  occurred 
during  the  operations  with  same,  which  speaks  greatly  in 
favour  of  its  safety  and  ability  of  keeping  a  homogeneous 
composition  of  the  flame ;  besides,  it  is  light  in  weight  and 
easy  to  handle. 

The  extent  of  the  hydrogen  welding  may  be  judged  from 


142  WELDING  AND   CUTTING  METALS 

the  production  of  the  gases  required ;  for  instance,  the 
UOxhydrique  Internationale,  at  Brussels,  produce  per  day  at 
their  works  200,000  litres  of  oxygen  and  400,000  litres  of 
hydrogen.  The  UOxliydrique  Frangaise,  Paris,  at  their 
works  at  Saint-Andre"-lez-Lille  (Nord)  ;  Beauval,  by  Trilport 
(Seine-et-Marne)  ;  Villeurbonne  (Ehone)  ;  and  Montbard 
(Cote-d'Or)  produce  per  day  more  than  600,000  litres  of 
oxygen  and  1,200,000  litres  of  hydrogen.  The  gases  are 
compressed  at  125  atmospheres  and  delivered  in  ordinary 
steel  cylinders,  which  latter  are  previously  tested  at  250 
atmospheres'  pressure. 

The  preference  given  to  hydrogen  welding,  particularly 
on  the  continent  of  Europe,  is  attributed  to  the  following 
facts,  as  summarised  by  L'Oxhydrique  Frangaise  :— 

COMPARISON  OF  HYDROGEN  AND  ACETYLENE  WELDING. 

HYDROGEN    WELDING.  ACETYLENE    WELDING. 

Installation. 

The  cost  of  the  hydrogen  The  cost  of  the  acetylene 
plant  is  from  £7  to  £15.  plant  varies  from  £36  to  £72, 

consequently  four  to  five 
hydrogen  plants  could  be 
obtained  for  the  same  ex- 
pense ;  besides,  the  acetylene 
generating  plant  cannot  last 
for  more  than  five  years, 
representing  an  amortisation 
of  nearly  Is.  per  day. 

By  using  acetylene-dissous, 
however,  the  generating  plant 
may  be  sound. 


HYDBOGEN  WELDING 


143 


Uncertainty. 


There  is  no  additional  ex- 
pense ;  the  above  price  in- 
cludes a  complete  hydrogen 


To  the  above  price  must  be 
added  the  cost  of  foundation 
and  installation  of  the  acety- 


immediate use. 


welding     plant     ready     for     lene    generator    and   washer, 

the  laying  of  water-pipes  for 
the  maintenance  of  the  gene- 
rator, and  a  costly  lead  piping 
for  the  conveyance  of  the 
acetylene. 

Facility  of  Installation. 


The  hydrogen  welding  plant 
does  not  require  any  installa- 
tion ;  furthermore,  it  may  be 
placed  anywhere. 


The  installation  requires 
official  authorisation  and 
approval  by  insurance  com- 
panies. The  generator  must 
be  surrounded  by  sufficient 
air  and  protected  against 
freezing  and  deterioration. 


Danger. 


During  a  period  of  five  years 
and  with  a  registered  number 
of  more  than  1,400  weldings, 
not  one  accident  has  been 
recorded. 


Notwithstanding  all  precau- 
tions taken,  more  than  ten 
fatal  accidents  have  occurred 
during  three  years,  besides 
those  which  have  taken  place 
in  the  use  of  acetylene  for 
other  purposes  than  welding. 

It  should  not  be  forgotten 
that  acetylene  is  the  most 
explosive  gas  existing. 


144 


WELDING  AND   CUTTING  METALS 


Application. 


The  hydrogen  blowpipe  is 
the  most  easy  to  handle. 

The  flame  is  not  regulated 
according  to  its  colour,  to  be 
judged  by  the  welder,  as  is 
the  case  with  the  acetylene 
welding,  but  by  a  special 
indicator,  which  produces  a 
saving  of  15  to  20  per  cent. 
as  compared  with  previous 
arrangements. 

The  blowpipe  is  everlast- 
ing, that  is  to  say,  is  replaced 
free  of  charge  in  case  of  being 
damaged. 

A  single  blowpipe  suffices 
for  welding  up  to  20  mm. 


The     hydrogen     blowpipe 
does  not  make  any  noise. 


The  acetylene  blowpipe  is 
difficult  to  regulate,  and  the 
welder  never  knows  if  the 
flame  is  of  an  oxidising  or 
reducing  nature,  there  being 
no  indicator  to  guide  him  in 
this  respect. 

This  explains  why  seventy 
reservoirs,  delivered  by  an 
eminent  French  firm,  were 
refused,  sixty  of  them  having 
split  during  the  tests,  although 
the  welding  appeared  perfect 
on  the  surface. 

It  requires  ten  different 
blowpipes  to  weld  the 
different  thicknesses  up  to 
20  mm.,  the  total  cost  of  the 
blowpipes  alone  amounting 
to  about  £50,  besides  the 
cost  of  their  replacing  when 
damaged. 

The  acetylene  blowpipe 
makes  a  deafening  noise. 


Instruction. 


Any  mechanic  can  learn 
the  handling  of  the  hydrogen 
blowpipe  in  a  few  hours' 


The  mechanic  seems  to  be 
sufficiently  instructed  as  soon 
as  he  can  make  a  weld,  but 


\ 

HYDROGEN  WELDING  145 

time,  by  reason  of  the  flame     the  weld  is  not  perfect.     It  is 
being  mechanically  regulated,     only  after  a  considerable  time 

he  can  become  a  proper 
welder.  M.  Le  Chatelier,  in 
Marseilles,  states  that  he 
never  permits  a  welder  to  do 
the  repair  of  a  steam  boiler 
unless  he  has  had  a  previous 
practice  in  welding  of  at  least 
eight  months. 

Poisoning. 

The  hydrogen  blowpipe  The  acetylene  blowpipe, 
gives  off  vapours  of  water  during  the  welding,  emanates 
only.  a  formidable  quantity  of  car- 

bonic oxide  besides  carbonic 
acid. 

This  is  even  admitted  by 
inventors  of  acetylene  blow- 
pipes, who  affirm  that  the 
quantity  of  oxygen  in  the 
blowpipe  does  not  permit  a 
transformation  of  this  carbon 
but  in  carbonic  oxide. 

Each  litre  of  acetylene  gives 
one  litre  of  carbonic  oxide. 

This  has  been  repudiated, 
basing  it  upon  analyses  made 
at  the  laboratories  under 
totally  different  conditions 
than  those  which  take  place 
at  the  welding  of  steel.  On 
w.  L 


146 


WELDING  AND   CUTTING  METALS 


the  other  hand,  it  has  been 
confirmed  by  the  evidence 
of  numerous  welders,  who 
complain,  after  one  or  two 
years'  welding  operations,  of 
pains  in  stomach  and  great 
anguish  in  the  chest,  nausea, 
etc. 


Economy. 


The  hydrogen  blowpipe, 
"Pyrox,  1907,"  is  very 
economical  by  reason  of — 

(1)  Its  low  price. 


(2)  Not 
cleaning, 
delay. 


requiring     any 
consequently      no 


(8)  The  hydrogen  blow- 
pipe, being  very  portable, 
minimum  of  time  is  lost  in 
replacing  the  welding  pieces. 


The  acetylene  blowpipe  is 
not  the  most  economical  by 
reason  of — 

(1)  Every   time  the    weld- 
ing   has     been    finished    the 
generator    still    continues    to 
generate  gas,   which   escapes 
into  the  atmosphere. 

(2)  Every  morning  it  takes 
at   least   one   hour    to   clean 
the  acetylene  apparatus  and 
to      remove      the      nauseous 
residues. 

By  using  acetylene-dissous 
the  generator  can  be  aban- 
doned. 

(3)  The    acetylene    blow- 
pipe,    being     less     portable, 
causes  troubles   and   expense 
in    its    displacement.      The 
generator  lasts   for   three    to 
five  years  only. 


WATER-GAS  WELDING  147 

Quality. 

Hydrogen  permits  welding  Acetylene  permits  the 
of  iron,  steel,  brass,  copper,  welding  of  iron  and  steel 
bronze  and  aluminium,  after  only.  The  weld  obtained  is- 
a  few  hours'  instruction.  not  malleable ;  it  is  hard  to 

file  and  brittle,  which  ex- 
plains why  it  should  not  be 
employed  for  pieces  which 
haveto  resist  a  certain  tension. 
Copper,  brass,  bronze,  or  alu- 
minium cannot  be  welded  by 
acetylene  by  reason  of  the 
great  temperature  it  produces. 

The  weight  of  the  hydrogen  The  weight  of  the  acetylene 
blowpipe  is  250  grammes.  blowpipe  varies  from  1  to  1*5 

kilogrammes. 

WATER-GAS  WELDING. 

To  overcome  the  difficulties  experienced  by  the  forging 
process  it  has  been  suggested  to  employ  the  water-gas,  which 
will  enable  the  parts  to  be  united  to  be  heated  locally  even  to> 
the  temperature  of  white  heat.  As  soon  as  the  temperature 
required  has  been  reached  the  heating  appliance  is  removed,, 
and  replaced  by  the  hammer  or  press. 

The  application  of  water-gas  is  connected  with  complicated 
and  expensive  installations  ;  besides,  the  high  percentage  of 
carbonic  oxide  which  the  water-gas  contains,  and  which  is. 
odourless,  has  caused  a  high  death  roll. 

The  water-gas  welding  has  found  application  principally  in. 
large  works  for  making  steam  boilers  and  tubes,  as  fully 
described  in  Chapter  V.,  page  168. 

It  is  stated  that  it  cannot  weld  plates  with  a  thickness  of 
less  than  one-fifth  of  an  inch. 

L  2 


CHAPTER   IV 

BLOWPIPES 

General  Eemarks — Daniel's  Burner — Hydrogen  Blowpipe — Schuckert — 
L'Oxhydrique  Internationale — Oxy-hydrogen  Blowpipe  Plant — 
Draeger-Wiss— Acetylene  Blowpipe  — High-pressure  Type — Low- 
pressure  Type — Acetylene  Illuminating  Company,  Limited — Fouche 
Blowpipe — Oxy-acetyleue  Blowpipe  Plant. 

GENERAL    REMARKS. 

THE  blowpipe  is  an  instrument  by  means  of  which  the 
operator  approaches  the  metal  upon  which  the  work  is  intended 
to  be  done,  while  by  the  old  system  the  metal  had  to  be 
brought  to  the  operator. 

The  blowpipe  provides  thus  a  method  of  dealing  very  simply 
with  an  immense  number  of  metallurgical  operations,  which 
have  until  quite  recently  been  carried  out  under  less  favourable 
conditions. 

The  various  systems  of  welding  seem,  however,  to  require  a 
special  form  of  blowpipe  ;  at  least,  each  system  claims  its  own 
construction  as  a  speciality.  Blowpipes  may  therefore  be 
classed  according  to  the  combustible  gas  which  they  employ, 
such  as  hydrogen,  acetylene,  ordinary  coal  gas,  and  naphtha  ; 
but  all  of  these  utilise  the  same  supporter  of  combustion  gas, 
oxygen. 

The  facility  by  which  oxygen  and  hydrogen  can  be  obtained 
for  commercial  purposes  drew  attention  to  the  possibilities  of 
the  oxy-hydrogen  blowpipe  as  a  welding  agent.  At  first 
Daniel's' burner  was  used,  the  gases  being  mixed  at  the  mouth 
of  the  burner  before  combustion,  but  without  satisfactory 


BLOWPIPES  149 

results.  Then  it  was  remembered  that  if  the  mixing  of  the 
gases  took  place  before  the  egression  from  the  burner,  their 
combustion  would  produce  a  higher  temperature.  This  is  the 
principle  upon  which  all  blowpipes  are  now  being  constructed. 
So  far  as  the  oxy-hydrogen  system  is  concerned,  the  mixing 
of  the  two  gases  may  take  place  either  outside  or  inside  *  the 
blowpipe.  Scliuckert,  for  instance,  mixes  the  gases  before 
they  enter  the  blowpipe,  and  employs  for  this  purpose  a  special 
mixing  chamber,  placed  about  1  metre  from  the  blowpipe. 
The  oxygen  and  hydrogen  are  passed  in  proper  proportions 
through  rubber  tubes  into  the  mixing  chamber.  The  mixture 


FIG.  83. 

travels  from  there,  by  means  of  a  rubber  tube,  into  the  blow- 
pipe, ready  for  combustion. 

In  most  cases,  however,  the  gases  are  mixed  in  the  blow- 
pipes. This  may  be  considered  to  be  the  safest  way  to  obtain 
a  proper  mixture  and  the  regulation  of  the  gases.  The 
Societe  Oxhydrique  Internationale  mix  the  oxygen  and  hydro- 
gen in  a  chamber  formed  in  the  mixing  part  of  the  tube, 
which  also  carries  the  burner.  DraejerrWiss,  according 
to  the  journal  Vulcan,  modifies  the  construction  by  placing 
the  channels  1  and  2  (Fig.  83)  for  the  oxygen  and  hydrogen 
in  an  oblique  position  towards  one  another,  and  by  producing 
a  suction,  prevents  the  gases  to  pass  into  the  tubes  of  one 
another  ;  the  mixture  of  the  two  gases  takes  place  in  a  larger 
chamber  before  it  enters  the  nozzle  3  for  combustion. 

The   Draeger-Wiss    blowpipe   is    based   upon    the   injector 


loO 


WELDING  AND   CUTTING  METALS 


No.  1,  for 
1  mm. 


No.  2,  for 
2  mm. 


No.  3,  for 
3  mm. 


No.  5,  for 
4—  o  mm. 


No.  7,  for 
o — 7  mm. 


No.  10,  for 
8—10  mm. 


No.  13,  f oi- 
lO— 13  mm. 


No.  16,  for 
13 — 16  mm. 


No.  20,  for 
16 — 20  mm. 


No.  2o,  for 
20 — 2o  mm. 


FIG.  84. — Acetylene  Blowpipe,  Draeger-Wiss,  Model  1908. 


BLOWPIPES  lol 

principle,  and  although  very  simple  in  its  construction  it 
nevertheless  embodies  the  qualities  required  of  an  effective 
blowpipe.  Fig.  84  shows  the  various  sizes  of  the  model  of 
1908  applicable  for  different  thicknesses  of  metal.  The 
blowpipe  is  as  suitable  for  hydrogen  as  for  acetylene,  and 
is  very  extensively  used  abroad. 

In  case  the  mixture  is  too  poor  in  oxygen,  the  combustion 
becomes  very  slow.  This  can  easily  be  verified  by  filling  a 
glass  tube  with  a  gas  mixture  poor  in  oxygen.  By  lighting 
the  mixture  at  one  end  of  the  tube  the  flame  may  be  seen 
travelling  towards  the  other  end  of  the  tube.  The  more 
oxygen  added  to  the  mixture,  the  faster  and  more  complete 
will  the  combustion  be;  when  it  has  reached  its  maximum, 
i.e.,  hydrogen  and  oxygen  in  the  proportion  of  2  :  1,  the 
activity  amounts  to  about  2,800  metres  per  second,  resulting 
in  an  explosion,  but  without  dangerous  effects.  Oxy-hydrogen 
blowpipe  plant  is  illustrated  in  Fig.  82  on  page  141. 

When  the  gases  are  burned  in  the  proportion  of  two  volumes 
of  hydrogen  to  one  volume  of  oxygen,  the  proportions  required 
for  complete  combustion,  the  temperature  of  the  flame  pro- 
duced is  about  6.000°  Fahr.  In  order,  however,  to  ensure  a 
non-oxidising  flame  which  cannot  injuriously  affect  the 
character  of  the  metal  operated  upon,  it  is  found  that  the 
gases  must  be  burned  in  the  proportion  of  about  four 
volumes  of  hydrogen  to  one  volume  of  oxygen,  so  that  the 
temperature  of  the  flame  produced  by  this  blowpipe  in  actual 
operation  is  probably  about  4,000°  Fahr. 

The  oxy-hydrogen  blowpipe  thus  constructed  supplied  to  a 
great  extent  what  was  wanted,  but  it  has,  like  all  other  con- 
structions of  blowpipes,  some  drawbacks,  which,  to  a  small 
extent,  will  reduce  its  general  use,  the  chief  one  being  that 
of  not  producing,  for  certain  purposes,  a  sufficiently  high  tem- 
perature ;  besides,  an  error  in  the  mixture,  however  small, 


152  WELDING  AND   CUTTING  METALS 

will  change  the  nature  of  the  flame  into  an  oxydising,  or 
reducing  one,  consequent  upon  an  excess  or  shortage  of 
oxygen.  Nevertheless,  the  oxy-hydrogen  blowpipe  renders 
quite  as  great  service  and  offers  similar  advantages  as  those 
of  other  blowpipe  systems,  which  is  testified  by  the  extreme 
extent  to  which  it  is  being  used  on  the  Continent. 

ACETYLENE  BLOWPIPE. 

The  intense  heat  generated  by  the  oxy-acetylene  flame  has 
resulted  in  various  constructions  of  blowpipes  for  this  welding 
system. 

It  is,  however,  not  practicable  to  compress  acetylene  in 
cylinders,  as  may  be  done  with  hydrogen,  because  of  its 
explosive  qualities  when  compressed,  Claude  and  Hess  having 
devised  the  acetone  solution  method. 

At  first  an  ordinary  form  of  blowpipe  was  used  for  burning 
acetylene  with  oxygen.  The  two  gases  were  kept  separate  up 
to  the  nozzle  of  the  blowpipe,  that  is  to  say,  to  the  actual 
point  of  combustion. 

With  acetylene,  however,  a  serious  inconvenience  appeared. 
A  heavy  deposit  of  carbon  took  place,  the  flame  was  sup- 
pressed, and,  indeed,  a  kind  of  carbon  mushroom  resulted. 
It  was  therefore  necessary  to  resort  to  some  sort  of  blowpipe 
in  which  the  mixture  of  gases  might  be  made  in  the  interior 
of  the  apparatus.  But  with  acetylene  a  serious  accident  was 
to  be  feared,  as  the  flame  might  flash  back  into  the  blowpipe 
and  cause  an  explosion. 

It  is  known  that  to  prevent  a  back  draught  of  the  flame  the 
issuing  gas  must  ordinarily  have  a  velocity  higher  than  that 
of  the  explosion  wave,  which,  for  a  mixture  of  oxygen  and 
acetylene,  is  extremely  high.  Practical  experience  proves  that 
it  is  not  necessary  to  attain  this  point  because  of  the  very 
small  section  of  the  blowpipe  nozzle.  A  velocity  of  flow 


BLOWPIPES  153 

equal  to  about  150  metres  a  second  is  sufficient  to  prevent  the 
flame  from  travelling  back  into  the  apparatus. 

In  further  prevention  of  this  return  of  the  flame  the 
interior  was  filled  with  a  porous  material,  but  this  made  it 
necessary  to  increase  the  pressure  to  the  equivalent  of  3  to  4 
metres  of  water. 

A  problem  still  to  be  solved  was  that  of  utilising  acetylene 
not  under  pressure,  that  is,  generated  immediately  in  the 
carbide  apparatus.  Fouclte  found  a  very  interesting  solution 
by  introducing  the  oxygen  into  the  apparatus  through  an 
injector,  which  draws  a  flow  of  acetylene  with  it.  The 
acetylene  enters  through  extremely  small  tubes,  which  do  not 
permit  the  passage  of  the  flame. 

There  are  now  in  general  use  two  types  of  oxy-acetylene 
blowpipes : 

High-pressure  type. 

Low-presure  type. 

The  High-pressure  blowpipe  is  one  in  which  both  the  gases 
are  used  under  pressur.e.  The  oxygen  is  supplied  from  an 
ordinary  trade  oxygen  cylinder,  and  the  acetylene  from  a 
cylinder  in  which  it  is  dissolved  in  acetone  absorbed  by  a 
porous  material. 

The  Acetylene  Illuminating  Company,  Limited,  give  the 
following  information  as  to  their  high-pressure  interchange- 
able blowpipes  :— 

INTERCHANGEABLE  BLOWPIPES  (HIGH-PRESSURE). 


No. 

Sizes. 

Consumption  of  Acetylene  per  hour  in  liti'es. 

A.D.  1 

5 

50,  75,  100,  150,  or  225 

A.D.  2 

6 

150,  225,  350,  500,  750,  or  1,000 

A.D.  3 

6 

500,  750,  1,000,  1,500,  2,000,  or  2,500 

No.  3  is  fitted  with  water  circulation  round  the  tip. 


154 


WELDING  AND   CUTTING  METALS 


The  standard  sizes  of  the  patent  high-pressure  blowpipes 
are  as  follows : — 


No. 

Consumption  qf  Acetylene 
per  hour  in  litres. 

H.P.    1 

25 

H.P.    2 

35 

H.P.    3 

50 

H.P.    4 

75 

H.P.    5 

100 

H.P.    6 

150 

H.P.    7 

225 

H.P.    8 

350 

H.P.    9 

500 

H.P.  10 

750 

H.P.  11 

1,000 

Note. — 28  litres  =  1  cubic  foot  approximately. 

The  Low-pressure  blowpipe  is  one  in  which  acetylene  is  used 
direct  from  a  gas-holder,  and  the  oxygen  from  a  trade 
cylinder.  This  system  is  suitable  for  use  in  workshops 
situated  in  districts  where  dissolved  acetylene  cannot  be 
obtained. 

LOW-PRESSURE  BLOWPIPES. 


No. 

Consumption  of  Acetylene 
per  hour  in  litres. 

L.P.    3 

50 

L.P.    4 

75 

L.P.    5 

100 

L.P.    6 

150 

L.P.    7 

225 

L.P.    8 

350 

L.P.    9 

500 

L.P.  10 

750 

L.P.  11 

1,000 

L.P.  12 

1,500 

LP.  13 

2,000 

BLOWPIPES  loo 

By  the  high-pressure  type  the  adjustment  of  the  flame  is 
far  easier  with  both  gases  under  pressure ;  once  the  adjust- 
ment is  made  right  it  remains  so  ;  a  more  intimate  mixing  of 
the  two  gases  is  obtained  than  in  the  low-pressure  type,  and 
this  secures  higher  efficiency.  This  is  a  point  of  great 
importance,  as  it  is  found  that  with  the  high-pressure  blow- 
pipe considerably  less  acetylene  is  required  to  do  a  fixed 
quantity  of  work  than  is  necessary  with  a  low-pressure  blow- 
pipe. 

For  some  time  experiments  have  been  going  on  to  perfect  a 
blowpipe  in  which  the  consumption  of  gas  could  be  regulated 
so  as  to  do  away  with  the  necessity  of  having  a  large  number 
of  different  sized  blowpipes.  Up  to  the  present  this  has  been 
found  to  be  quite  impossible  in  the  low-pressure  type  of  blow- 
pipe, but  blowpipes  on  the  high-pressure  system  admit  the 
gas  consumption  to  be  altered  over  a  wide  range  by  merely 
changing  the  nozzle.  In  this  type  of  blowpipe  both  gases  are 
used  at  the  same  pressure,  which  has  the  great  advantage 
that  if,  while  the  work  is  going  on,  the  orifice  of  the  nozzle 
becomes  partly  choked  by  scale  from  the  metal,  the  composi- 
tion of  the  flame  remains  the  same,  but  in  the  case  of  a  low- 
pressure  blowpipe,  where  the  oxygen  is  introduced  at  a  high 
pressure  and  in  a  constant  quantity,  and  the  acetylene  at  a 
low  pressure,  any  choking  of  the  orifice  will  result  in  an 
alteration  of  the  composition  of  the  flame  and  consequent 
oxidation  of  the  metal. 

The  Acetylene  Illuminating  Company  give  (on  pages  153 
to  157)  tables  of  practical  instruction  for  using  their  blow- 
pipes. 

When  a  blowpipe  is  working  properly  the  length  of  the 
small  white  cone  of  the  flame  for  the  different  blowpipes 
should  be  as  in  the  following  table : — 


156 


WELDING  AND   CUTTING  METALS 


Consumption  of 
Acetylene  per 
hour  in  litres. 

Length  of  cone 
in  mm. 

Consumption  of 
Acetylene  per 
hour  in  litres. 

Length  of  cone 
in  mm. 

50 

6 

500 

10 

75 

6-5 

750 

11 

100 

7 

1000 

12 

150 

7-5 

1500 

13 

225 

8 

2000 

14 

350 

9 

2500 

15 

The  approximate  internal  diameter  in  inches  of  pipe 
required  between  the  acetylene  apparatus  and  the  hydraulic 
back-pressure  valve : 


Quantity  of  Acetylene  required  per  hour, 
in  cubic  feet. 

10 

25 

50 

75 

50 

§ 

f 

1 

1* 

Distance    in    feet 

100 

t 

1 

1J 

4 

between  acetylene 

200 

1 

1 

11 

11 

generator     and 

500 

I 

1 

11 

i* 

hydraulic       back- 

1000 

1 

li 

1^ 

H 

pressure  valve. 

2000 

1 

1} 

li 

2 

3000 

li 

1* 

2 

2i 

Speed  at  which  Work  can  be  Welded  and  Proper  Size  of  Bloiv- 
pipe  to  Use. — The  table  on  p.  157  shows  the  approximate  size 
of  blowpipe  to  be  used  on  different  thicknesses  of  metal  and  the 
approximate  rate  at  which  work  can  be  welded.  Allowance 
must  be  made  for  the  skill  of  the  workman,  the  character  of 
the  job,  and  the  type  of  blowpipe  employed.  The  sizes  of 
blowpipes  given  in  the  table  are  of  the  high-pressure  type ;  it 
will  be  found  that  a  larger  blowpipe  will  be  required  when 
low-pressure  plants  are  in  use. 

The  Fouche  blowpipe  is  a  French  invention  based  upon  the 
injector  principle.  It  was  introduced  a  few  years  since,  and 
has  recently  undergone  some  further  improvements. 


BLOWPIPES 


157 


Experience  has  already  confirmed,  to  a  certain  extent,  what 
science  has  taught,  that  a  proper  weld  is  vitally  dependent 
upon  various  matters,  the  foremost  amongst  which  are  the 
absolute  purity  of  the  gases  employed,  the  composition  and 
continuity  of  their  mixture  and  its  velocity  at  the  nozzle  of 
the  blowpipe,  the  pressure  and  temperature  of  the  flame  and 
its  application  upon  the  metals  to  be  welded.  Furthermore, 
consideration  must  also  be  taken  as  to  the  thickness  as  well 
as  the  chemical  and  physical  properties  of  the  welding  metal. 


Thickness  of  Plate 
in  m.m. 

Size  of  Blowpipe 
to  use. 

Speed  of  work  in  foot 
run  of  weld  per  hour. 

1 

3 

50 

1-5 

4 

40 

2 

5 

35 

2-5 

6 

30 

3 

7 

24 

4 

8 

18 

5-6 

9 

14 

7'8 

10 

10 

9-10 

11 

7 

11-25 

3  A.D. 

The  orifice  of  the  nozzle  must  be  constructed  accordingly,  and 
the  blowpipe  must  be  light  and  easy  to  handle. 

The  velocity  of  the  gas  mixture  when  it  leaves  the  nozzle 
must  not  be  too  great,  as  it  would  prevent  the  controlling  of 
the  welded  metal  with  the  flame,  nor  should  it  be  too  sm.all, 
as  it  would  then  cause  the  flame  to  repel  or  to  be  driven  back. 

With  a  consumption  of  3,000  litres  of  acetylene  per  hour, 
for  instance,  the  working  pressure  should  not  exceed  three 
atmospheres,  and  when  the  consumption  is  smaller  it  should 
be  reduced  accordingly,  even  to  0*5  atmosphere.  The  velocity 
of  the  gas  would  in  such  a  case  not  exceed  250  metres  per 
second. 


158 


WELDING  AND   CUTTING  METALS 


A  constant  gas  consumption,  combined  with  a  constant 
pressure  and  the  largest  orifice  possible  of  the  nozzle,  con- 
stitutes the  best  burner. 

It  is  evident,  therefore, 
that  the  construction  of  a 
blowpipe  must  in  the  first 
instance  be  based  upon 
theoretical  principles,  and 
the  wide  range  of  its  ap- 
plication adds  consider- 
ably to  the  difficulties  of 
its  construction. 

The  more  exact  and 
minutely  correct  in  its 
construction  the  more  will 
the  blowpipe  comply  with 
the  theoretical  conditions, 
and  the  more  perfect  will 
be  the  weld. 

Fonche  has  complied 
with  these  conditions  by 
producing  twelve  different 
sizes  of  blowpipes  of  such 
a  correctness  that  only 
can  be  produced  with  the 
most  sensitive  instru- 
ments. Other  systems 
are  generally  satisfied 
with  four  or  five  different 


FIG.  <S«3. — Fouche  Blowpipe. 


sizes  of  blowpipes  for  doing  the  same  work,  pointing  out  this 
as  a  great  advantage  by  reason  of  saving  expense  to  the  welder. 
There  is  nothing  to  prevent  a  reduction  in  the  number  of 
sizes  of  the  Fouche  blowpipes,  but  this  could  only  be  done  by 


BLOWPIPES  159 

raising  the  working  pressure  in  order  to  increase  the  working 
effect,  which  would  result  in  an  unsatisfactory  weld. 

A  greater  volume  can  certainly  be  obtained  by  working  with 
a  greater  gas  pressure,  but  the  velocity  of  the  gas  mixture  at 
the  egress  of  the  nozzle  must  remain  unaltered.  This  is  only 
possible  when  the  oxygen  injector  and  the  mixing  chamber  as 
well  as  the  orifice  of  the  nozzle  are  all  simultaneously  altered. 
But  the  most  important  is  that  the  mixture  of  the  gases  remains 
constant  and  does  not  decompose  in  any  way. 

The   unavoidable    heating   of    the    blowpipe   by   radiation 


FIG.  86.— Fouche  Cyklop  Blowpipe. 

of  heat  from  the  welding  pieces  will  act  differently  upon  the 
oxygen,  which  is  introduced  at  a  high  pressure  and  in  a 
constant  quantity,  and  on  the  acetylene,  at  a  low  pressure, 
and  will  cause,  after  a  few  minutes'  working,  an  alteration  in 
the  composition  of  the  flame,  which  will  become  more  and  more 
rich  in  oxygen  with  corresponding  oxidation  of  the  welding 
metal.  An  attentive  and  skilful  welder  can  notice  these  effects 
from  the  appearance  of  the  flame,  and  will  therefore  stop  the 
welding  in  order  to  cool  the  blowpipe  or  change  the  nozzle. 
The  Fouche  blowpipe,  1908,  avoids  all  these  disadvantages 


160 


WELDING  AND   CUTTING  METALS 


mechanically,  and  retains  absolutely  the  reducing  property  of 
the  gas  mixture,  while  its  weight  is  only  one-third  of  that  of 
the  former  construction  (Fig.  85). 

The  following  table  shows  the  approximate  consumption  of 
acetylene  by  the  various  sizes  of  Fouche's  low-pressure  blow- 
pipes, 1908,  for  different  thicknesses  of  plate  :— 

FOUCHE  BLOWPIPE. 


No.  of  Blowpipe. 

Thickness  of 
Plate  in  mm. 

Consumption  of 
Acetylene  in  litres 
per  hour. 

2 

0*5 

36 

3 

r 

75 

4 

2- 

130 

5 

3' 

210 

6 

3—5 

300 

7 

5—7 

450 

8 

7—10 

650 

10 

10—13 

1000 

12 

13—16 

1500 

15 

16—25 

2200 

FOUCHE  CYKLOP  BLOWPIPE. — FIG.  86. 


No.  of  Blowpipe. 

Thickness  of 
Plate  in  mm. 

Consumption  of 
Acetylene  in  litres 
per  hour. 

2 

0-5 

36 

3 

1- 

75 

4 

2' 

100 

5 

3* 

150 

6 

3—5 

225 

7 

5—7 

350 

8 

7—10 

500 

10 

10—13 

750 

12 

13—16 

1000 

15 

16—25 

2000 

16 

25—30 

2500 

BLOWPIPES 


161 


In  workshops  where  various  welders  are  engaged,  it  is  advis- 
able to  have  several  blowpipes,  but  where  repairing  work  is 
principally  being  done,  or  where  one  welder  only  is  operating, 
a  Fouche  Gigant  blowpipe  would  be  the  best  to  use. 

In  the  Fouche  Gigant,  the  oxygen  injector,  the  suction, 
nozzle  and  the  head  of  the  blowpipe  form  all  one  solid  piece 
which  may  be  removed  in  one  single  operation;  while  in 
other  similar  burners  the  nozzle  only  and  not  the  oxygen 
injector  is  generally  exchangeable.  The  most  favourable 
velocity  of  the  gas  mixture,  and  consequently  also  the 
rational  working,  is  thereby  secured ;  any  confusion  in 
employing  a  wrong  nozzle  is  prevented  and  thus  waste  of 
gas  avoided. 

Fouche  Gigant  No.  1,  with  five  exchangeable  parts,  represents 
the  blowpipes  Nos.  2,  3,  4,  5  and  6 ;  Fouche  Gigant  No.  2, 
with  six  exchangeable  parts,  the  blowpipes  Nos.  4,  5,  6,  7,  8 
and  10 ;  Fouche  Gigant  No.  3,  with  three  exchangeable  parts, 
the  blowpipes  Nos.  12,  15  and  16.  The  Fouche  blowpipes  can 
be  used  either  for  low  or  high  pressure. 

Dr.  Michaelis  gives  the  sizes  of  the  piping  between  the 
gasometer  and  the  weld  by  Fouche's  blowpipe  as  follows :— 


Quantity  of  Acetylene  required  per  hours  in  litres. 

Distance  in  Metres 
from  Gasometer 

80 

100 

200 

300 

500 

1000 

2000 

3000 

to  weld. 

Internal  diameter  of  pipe  in  m.m. 

10 

10 

10 

10 

13 

20 

20 

26 

32 

20 

10 

10 

13 

13 

20 

26 

32 

32 

30 

10 

10 

13 

20 

20 

26 

32 

40 

40 

10 

10 

13 

20 

20 

26 

32 

40 

50 

10 

10 

20 

20 

20 

26 

40 

50 

75 

10 

13 

20 

20 

26 

32 

40 

50 

100 

13 

13 

20 

20 

26 

32 

40 

50 

200 

13 

13 

20 

20 

26 

40 

50 

60 

500 

20 

20 

26 

26 

32 

40 

60 

80 

1000 

20 

20 

26 

26 

40 

50 

60 

80 

162 


WELDING  AND   CUTTING  METALS 


Fig.  87  is  an  illustration  of  a  complete  low  pressure  oxy- 
acetylene  plant  without  the  acetylene  generator,  which  may 
be  placed  in  any  suitable  position,  preferably  outside  and  at 


FIG.  87.— Low-pressure  Oxy-acetylene  Plant,  without  the  Generator. 

any  distance  from  the  blowpipe,  and  its  connection  with  the 
blowpipe. 

A  is  a  tap  connecting  the  inlet  to  the  hydraulic  safety  valve 
with  the  acetylene  supply  pipe  from  the  acetylene  apparatus. 

The  blowpipe  is  connected  at  a  by  means  of  an  ordinary 
stout  rubber  tube  with  the  outlet  tap  B  of  the  hydraulic  safety 
valve.  This  forms  the  acetylene  supply  pipe  to  the  blowpipe. 


BLOWPIPES  163 

The  blowpipe  is  connected  at  0  by  means  of  a  special 
canvas-covered  strong  rubber  pipe  with  the  outlet  tap  T  of  the 
oxygen  pressure  regulator,  which  is  fixed,  as  shown,  on  the 
oxygen  cylinder. 

This  pipe  conveys  the  oxygen  supply  to  the  blowpipe,  and 
should  be  securely  attached,  as  it  is  subject  to  pressures 
varying  from  10  Ibs.  to  20  Ibs.  per  square  inch. 

The  hydraulic  safety  valve  is  supposed  to  have  been  pre- 
viously charged  with  water,  and  the  gas  regulator  securely 
attached  to  the  oxygen  cylinder. 

The  blowpipe  apparatus  is  now  ready  for  use,  with  the  taps 
A,  B,  and  T  closed. 

First  open  the  cylinder  valve  by  means  of  the  key  supplied 
for  that  purpose.  Then  by  means  of  the  thumb-screw,  P, 
adjust  the  pressure  of  the  low-pressure  gauge,  I,  to  the  correct 
working  pressure  for  the  blowpipe  used.  Then  open  the  taps 
A,  B,  and  a,  and  when  acetylene  is  unmistakably  smelt  at  the 
nozzle  of  the  blowpipe,  ignite  it  by  means  of  a  gas  jet,  candle,, 
or  taper.  Then  open  the  tap  T,  which  admits  oxygen  to  the 
blowpipe,  and  correct  the  pressure  on  the  gauge,  I  (which  will 
be  found  to  have  dropped  slightly  through  the  tap  being 
opened).  Then  by  means  of  the  tap  a  slowly  throttle  down 
the  acetylene  until  the  small  white  cone  of  flame  at  the  nozzle 
of  the  blowpipe  shows  a  clearly  defined  outline. 

The  tap  A  must  never  be  used  to  regulate  the  supply  of 
acetylene ;  in  fact,  after  the  hydraulic  safety  valve  has  been 
charged  with  water  it  is  best  to  leave  this  tap  always  on. 

The  pressure  of  the  acetylene  supply  due  to  the  gas-holder 
should  be  not  less  than  5  ins.  of  water,  and  the  supply  pipe 
should  be  proportioned  to  the  maximum  quantity  required  per 
hour.  It  is  a  good  plan  to  fix  a  water-pressure  gauge  near 
the  inlet  to  the  hydraulic  safety  valve  in  order  to  note  the 
pressure  supply  during  work. 

M2 


164  WELDING  AND   CUTTING  METALS 

On  stopping  work  the  acetylene  taps  a  or  B  should  be  closed 
first  and  then  the  oxygen  tap  T.  When  work  is  completely 
stopped  the  oxygen  cylinder  should  be  shut  off  also,  and  the 
pressure  released  from  the  regulator. 

When  the  apparatus  is  ready  for  operation,  the  welding 
should  be  done  at  the  apex  or  outer  extremity  of  the  small 
bright  green  cone,  which  by  the  Fouche  burner  retains  its 
radiating  brightness  and  size,  about  10  to  15  m.m. 

The  mixture  of  gas  being  ignited  at  the  orifice  of  the  burner, 
the  acetylene  will  at  the  moment  of  combustion  with  oxygen 
decompose  into  its  elements,  carbon  and  hydrogen.  The 
carbon  takes  part  in  the  burning  only,  while  the  hydrogen, 
not  being  able  to  combine  with  the  oxygen  at  the  very  high 
temperature  in  the  neighbourhood  of  the  flame,  remains  tem- 
porarily in  its  free  state.  The  flame  consists  almost  entirely 
of  carbon  monoxide,  which  is  being  converted  at  its  extremity 
into  carbon  dioxide.  The  free  hydrogen  forms  round  the 
flame  a  relatively  cool  jacket,  and  protects  the  inner  zone 
from  loss  of  heat,  and  excludes  almost  any  possibility  of  oxida- 
tion. The  small  white  cone  formed  in  the  centre  of  the  flame 
has  at  its  apex  a  temperature  of  about  1,300°  Fahr. 

In  order  to  obtain  a  perfect  combustion  two  and  a  half 
volumes  of  oxygen  to  each  volume  of  acetylene  are  theoretically 
required,  but  in  practice  it  has  been  found  that  about  equal 
volumes  of  the  two  gases  will  suffice,  dependent,  however, 
upon  the  purity  of  the  gases  and  the  regulating  power  of  the 
blowpipe. 

The  blowpipe  should  never  be  kept  in  such  a  position  as  to 
enable  the  flame,  thrown  back  from  the  weld,  to  strike  the 
head  of  the  burner. 

If  the  flame  is  not  properly  regulated,  it  may  fire  back  and 
go  out.  If  so,  the  hydraulic  safety  valve  should  be  closed  at 
once,  and  a  few  seconds  allowed  to  elapse  before  relighting. 


BLOWPIPES  ir,5 

The  extinguishing  of  the  flame  may  be  attributed  to  some  of 
the  following  reasons  :— 

(a)  Deficiency  in  the  oxygen  pressure.     See  that  the  oxygen 
pressure  regulator  is  properly  arranged,  and  that  the  vessel 
is  open. 

(b)  Heating  of  the  nozzle  of  the  burner,  for  instance,  by 
working  a  deep  weld  or  by  placing  the  blowpipe  in  a  very 
acute  angle,  enabling  the  flame  to  strike  back  around  the  head 
of  the  burner.     In  this  case  it  is  advisable  to  cool  the  burner 
in  a  bucket  of  water  after  first  turning  out  the  flame. 

(c)  Choking   of   the   orifice    in    the  nozzle  of  the   burner 
through  beads  of  iron  being  splashed  into  it,  or  from  any 
other  cause,  in  which  case  it  should  be  cleaned  with  a  wire 
brush.     No  other  sharp  instrument  should  be  used  in  the 
holes. 

The  great  advantage  of  blowpipe  welding  is  that  it  is  quite 
as  applicable  to  mild  steel  as  to  iron,  and  that  it  permits  the 
welding  of  thin  plates,  which  were  heretofore  riveted  or  clinched 
together. 

The  blowpipe  is  further  most  valuable  for  use  whenever  it 
is  necessary  to  work  upon  parts  already  in  place,  permitting 
the  manufacture  of  forms  of  articles  requiring  numerous  and 
complicated  joints,  impossible  to  manufacture  by  forging.  It 
has  the  further  advantage  of  being  a  light  apparatus,  easily 
manipulated  and  requiring  no  elaborate  installation. 

At  first  sight  it  might  appear  that  the  melted  or  cast  metal 
produced  would  not  have  the  qualities  of  strength,  and  parti- 
cularly that  of  elasticity,  shown  by  rolled  or  hammered 
material.  Surprising  results,  however,  are  obtained  unless 
care  is  taken  during  the  process  to  avoid  overheating  or  oxida- 
tion of  the  metal,  or  its  alteration  by  the  introduction  of 
impurities  such  as  sulphur  or  phosphorus.  If,  for  example, 
thin  sheets  or  tubes  of  a  few  millimetres  thickness  are  subjected 


166  WELDING  AND   CUTTING  METALS 

to  a  light  hammering  or  even  a  mild  tempering,  the  metal 
will  be  found  perfectly  ductile,  and  the  weld  will  exhibit  a 
strength  almost  equal  to  the  resistance  of  the  original  metal. 
Tubes  thus  welded  may  be  crushed  or  twisted,  and  plates  may 
be  bent  and  refolded,  following  the  weld,  without  showing  any 
cracks. 

When  it  comes  to  the  welding  of  comparatively  thick  plates 
such  as  those  of  boilers,  the  problem  is  more  complicated, 
because  of  the  greater  difficulty  of  producing  uniform  and 
thorough  fusion  to  a  thickness  exceeding  6  or  8  m.m. 
Under  such  conditions  use  is  often  made  of  an  artifice 
which  should  be  condemned,  and  which  has  to  some  extent 
discredited  autogenous  welding  of  heavy  plates. 

This  artifice  consists  in  chamfering  both  edges  which  are  to 
be  joined,  and  filling  the  space  thus  left  by  melting  an  iron 
rod  in  the  blowpipe  flame.  The  procedure  is  not  absolutely 
bad  if  it  is  very  skilfully  carried  out  and  if  the  operator  is 
careful  to  use  a  flame  heating  a  large  area  and  to  let  the  drop 
of  melted  metal  fall  only  on  the  part  of  the  weld  which  has 
already  been  raised  to  the  fusion  temperature. 

It  is.  easily  seen  what  extreme  attention  is  necessary  to 
succeed  in  manipulation  of  this  kind.  If  it  is  badly  done,  a 
poor  adhesion  is  obtained;  if  it  is  well  done,  the  relatively 
large  quantity  of  melted  metal  introduced  between  the  two 
edges  lowers  the  strength  and  destroys  the  ductility.  Test 
pieces  submitted  to  tension  break  without  elongation. 

The  general  procedure  of  welding  plates  from  6  to  25  m.m. 
thickness  is  as  follows  :— 

The  two  pieces  to  be  joined  are  brought  edge  to  edge  with- 
out superposition  in  perfect  contact ;  if  necessary  to  secure 
this,  they  are  first  subjected  to  a  light  cut  on  the  planer  ;  they 
are  then  heated  by  means  of  two  blowpipes,  one  above  and  one 
below,  exactly  opposite  to  one  another,  and  producing  as  large 


BLOWPIPES  167 

a  heated  zone  as  possible.  When  fusion  begins  to  appear  on 
the  surface  it  is  probable  that  the  interior  of  the  plate  is  at 
white  welding  heat.  The  blowpipes  are  then  withdrawn,  and 
by  a  simple  mechanical  arrangement  they  are  replaced  by  an 
anvil  and  a  very  light  hammer,  not  exceeding  one  or  two 
kilogrammes  weight.  The  blow  of  this  hammer  is  sufficient 
to  cause  a  consolidation  of  the  metal  along  the  two  butting 
edges. 

Perfect  welding  is  secured,  and  it  is  probable  that  the  light 
hammering  produces  at  the  same  time  a  certain  orientation  of 
the  molecules  favourable  to  the  elastic  properties  of  the  metal. 
In  fact,  if  test  pieces  of  metal  so  welded  are  tested  under 
tension  to  the  breaking  point,  it  is  found  that  the  grain  of  the 
fracture  is  not  that  characteristic  of  cast  specimens,  but  is 
perfectly  t  homogeneous  and  like  that  of  the  original  plate. 
The  strength  is  but  a  small  percentage  less  than  the  original, 
and  the  elongation  is  satisfactory. 

Metal  of  a  tensile  strength  of  36  to  38  kilometres  and  elonga- 
tion of  25  to  28  per  cent,  shows  after  welding  a  tensile  strength 
of  36  kilometres  and  elongation  of  13  per  cent.  These  results 
are  satisfactory  for  the  majority  of  cases  in  which  it  is  desirable 
to  substitute  for  riveting  the  process  of  welding. 


CHAPTEK  V 

WELDING    OF    SHEET    IRON 

Patent  Welded  Tubes — Seamless  Tubes— Pioneer  of  Water  Gas  Welding — 
Various  Methods  used — Schematic  View  of  Welding  by  Coke  Fire  and 
Water  Gas — Articles  of  Complicated  Form — Relative  Strength  of 
Welded  and  Riveted  Seams— Testing  Methods— Durability  of  Welded 
Seams— Welded  Tubes  for  Water  Mains— Steel  Pipes— Relative 
Advantages  of  Cast  Iron  and  Steel  Pipes — Relative  Strength  of 
Riveted  and  Welded  Pipes — Relative  Cost  of  Cast  Iron  Pipes,  Steel 
Pipes,  and  Riveted  Pipes — Relative  Corrosion  of  Wrought  Iron,  Soft 
Steel,  and  Nickel  Steel. 

THE  welding  of  sheet  iron  on  a  commercial  scale  is  effected 
by  means  of  water  gas  or  electricity. 

It  was  for  a  long  time  considered  as  a  work  of  art,  and  was 
therefore  left  in  the  hands  of  a  few,  who  preferred  to  keep 
the  process  as  a  secret. 

This  may  be  the  reason  why,  even  at  the  present  time,  so 
little  is  known  about  this  industry,  and  why  there  is  an  entire 
absence  of  literature  upon  the  subject. 

By  examination  it  will  be  found,  however,  that  welding  of 
plates  of  iron  and  mild  steel  is  an  important  industry, 
extending  its  applications  almost  daily  upon  articles  of  the 
most  complicated  forms  ;  but,  unfortunately,  the  faults  of  the 
old  workers  are  strictly  adhered  to  by  the  present  ones  by 
keeping  the  various  processes,  and  more  particularly  the 
mechanical  appliances,  as  a  secret. 

It  is  not  generally  known  that  the  manufacture  of  "  patent 
welded "  and  "  seamless "  tubes  ceases  with  a  diameter  of 
about  300  m.m.,  and  that  the  present  systems  of  welding 
sheet  iron  have  taken  their  place  by  turning  out  pipes  of  any 


WELDING  OF   SHEET   IRON  169 

diameter  and  length,  limited  only  by  regulations  of  transit, 
such  pipes  being  preferable  for  high-pressure  strain  instal- 
lations, water,  gas,  and  air  conduits  of  every  description. 

It  is  interesting  to  note  that  the  pioneer  of  water  gas  welding 
was  F.  Fitzner,  of  Laurahiitte,  Ober  Schlesien,  Kommer- 
zienrat,  who  some  thirty  years  since  conceived  the  idea  of 
applying  welding  to  the  manufacture  of  pipes.  He  has 
gradually  provided  new  and  necessary  mechanical  appliances, 
ingeniously  constructed,  for  the  welding  of  articles  of  almost 
any  shape  and  form.  The  process  which  is  employed  by 

FIG.  88.  FIG.  89. 


FIG.  90. 

him  is  the  water  gas  system,  whereby  any  kind  of  iron 
and  steel — Siemens-Martin  or  Thomas — may  be  welded.  It  is 
generally  easier  to  weld  mild  metal  than  hard,  and  up  to  a 
strength  of  45  kg/  9  cm.  Even  hard  steel  plates  may  be 
welded,  but  the  elasticity  at  the  welding  seam  is  reduced. 
The  welding  of  steel  plates  has,  therefore,  a  limited  field. 

The  various  methods  used  in  welding  of  sheet  iron  are  :— 

End-to-end  welding  (Fig.  88)  ; 

Lap  welding  (Fig.  89) ; 

Wedge  welding  (Fig.  90). 

The  end-to-end  welding  is  limited  to  the  welding  of  flanges. 

The  lap  welding  is  mostly  used  for  all  plates  up  to  a 
thickness  of  20  m.m. 


170 


WELDING  AND   CUTTING  METALS 


The  wedge  welding  may  be  safely  applied  to  thicknesses 
up  to  50  m.m.  ;  plates  of  greater  thickness  may  also  be 
welded ;  but  in  that  case  the  ordinary  mechanical  means  for 
pressing  the  welded  joints  together  are  insufficient,  and  must 
be  substituted  by  hammers  and  the  like  worked  by  steam  or 
hydraulic  power. 

The  heat  required  to  complete  the  weld  is  obtained  either 
from  coke  fire,  which  may  be  stationary  or  portable,  or  from 
water  gas.  The  water  gas  is  mixed  with  atmospheric  air  and 


FIG.  91. 


FIG.  92. 


passed  into  special  burners,  which  may  be  stationary  or 
portable,  and  the  flame  is  made  to  act  upon  the  plates  to  be 
welded.  The  combustion  is  very  satisfactory,  and  leaves  a 
flame  of  great  purity,  the  temperature  of  which  is  easily 
recognised  and  regulated  during  the  time  of  operation. 

A  special  advantage  is  obtained  by  the  use  of  two  burners, 
one  on  each  side  of  the  seam,  producing  thereby  an  almost 
homogeneous  temperature,  penetrating  the  whole  thickness  of 
the  plates. 

Figs.  91  and  92  give  a  schematic  view  of  welding  by  coke  fire 
and  by  water  gas.  A  is  the  anvil  on  which  the  weld  is  being 
completed  after  it  has  been  brought  to  the  proper  temperature  ; 


WELDING  OF   SHEET  IRON  171 

BB  are  the  two  water  gas  burners,  applied  on  each  side  of 
the  seam ;  and  C  is  the  coke  fire.  It  is  evident  that  by  the 
use  of  coke  fire  the  weld  must  be  turned  180°  in  order 
to  reach  the  anvil,  while  by  the  water  gas  90°  only  are 
required.  Instead  of  such  a  circular  turning,  a  longitudinal 
motion  may  be  given  to  the  welding  plates. 

But  it  is  very  seldom  that  the  welding  can  be  accomplished 
in  such  a  simple  manner.  The  more  complicated  the  shape  or 
form  of  the  article  to  be  produced,  the  more  ingenious  must 
the  mechanical  appliances  be. 

The  usual  method  of  welding  gas-pipes  and  patent  welded 
tubes  consists  in  welding  at  once  by  means  of  one  or  several 
heatings  along  the  whole  length  of  the  pipe.  Welding  by 
water  gas,  on  the  other  hand,  is  effected  by  several  heatings, 
one  after  the  other,  the  length  of  which  varies  from  100  to 
300  m.m.,  according  to  circumstances,  no  flux  of  any  kind 
being  used. 

What  security  offers  a  welded  tube  as  compared  with  a 
riveted  one  ?  The  strength  of  a  riveted  seam  amounts 
generally  to  55  per  cent,  of  that  of  the  plate  by  single  lap 
riveting,  70  per  cent,  by  double-riveted  and  75  per  cent,  by 
thrice-riveted  lap  when  reference  is  made  as  to  tightness  and 
solidity  of  riveting.  In  respect  of  cost  the  single  lap  riveting 
can  scarcely  be  compared  with  that  of  welding ;  therefore  it 
remains  to  compare  it  with  the  riveted  seam  of  70  per  cent, 
strength. 

A  welded  seam  gives  almost  the  same  strength  as  that  of 
the  plate  it  joins,  the  range  of  strength  varying  between  95 
and  100  ;  therefore  a  strength  of  90  to  95  per  cent,  of  a 
welded  seam  is  always  guaranteed,  and  experience  has  proved 
this  to  be  within  the  range. 

But  it  may  be  remarked  that  it  is  not  always  possible  to 
obtain  test  pieces  of  the  article  in  question  without  doing  harm 


172 


WELDING  AND   CUTTING  METALS 


WELDING  OF  SHEET  IEON 


173 


174 


WELDING  AND   CUTTING  METALS 


to  some,  but  in  such  cases  other  means  of  testing  are  at  disposal, 
such  as  water  pressure,  loading,  bending,  falling,  and  the  prac- 


20  atm. 


EiG.  95. 


tical  application  of  such  tests  is  very  extensive  indeed.     So, 
for  instance,  are  the  mains  for  water  supply  tested  by  water 


35  atm. 


5  cbm 


2550- 


FlG.  96. 


pressure,  masts,  yards,  etc.,  by  water  pressure  and  weight, 
bootsdavits  and  pillars  by  weight,  in  order  to  ascertain  the 
alteration  or  change  in  their  form. 

Fi'Ts.  93  and  94  show  bending  tests  of  bootsdavits  as  carried 


WELDING  OF  SHEET  IKON 


175 


out  at  the  Imperial  arsenal 
of  Dantzig,  with  the  excellent 
results  obtained.  It  may  he 
of  interest  to  mention  that 
Lloyds  have  approved  the 
ship  masts  as  delivered  by 
F.  Fitzner. 

A  special  feature  of  the 
durability  of  welded  seams  is 
given  by  their  application  to 
the  conduits  of  air  for  the 
ventilation  of  mines,  one  of 
the  most  severe  tests  to  which 
a  pipe  may  be  exposed  being 
used  day  and  night  in  a  very 
variable  humidity,  and  con- 
sequently exposed  to  a  par 
ticularly  great  strain. 

As  compared  with  riveting 
the  advantage  offered  by  weld- 
ing is  strikingly  apparent 
where  importance  is  attached 
to  saving  of  material,  where 
a  smooth  surface  is  desired 
or  is  a  condition,  and  where 
permanent  compactness,  even 
against  fire  and  the  action  of 
acids,  is  a  desideratum. 

The  principal  articles  pro- 
duced by  welding  of  plates  are 
tubes  and  pipes  of  every  kind 
and  size,  with  diameter  rang- 
ing from  200  up  to  1,500  m.m. 


0SZ- 


176 


WELDING  AND   CUTTING  METALS 


and  of   any  desired   length,  limited   only  by  the   means   of 
transit,  which,  for  instance,  by  rail  is  about  42  m. 

The  manufacture  of  welded  tubes  for  water  mains  has  con- 
siderably increased,  the  municipalities  having  fear  for  the 
rust  and  therefore  ordering  welded  pipes  of  mild  steel.  Besides, 


FIG.  98. 

the  manufacture  of  welded  tubes  offers  no  difficulties,  while 
other  articles  require  almost  every  ingenuity  in  order  to  be 
carried  out  by  welding.  A  few  of  those  being  frequently 
required  are  shown  in  Figs.  95,  96,  97.  Amongst  those  offering 
peculiar  difficulties  in  the  manufacture  is  the  vessel  shown  in 
Fig.  98,  just  immediately  after  completion  of  the  weld, 
without  any  kind  of  improvement  of  the  surface  in  order  to 


178 


WELDING  AND   CUTTING  METALS 


I 


WELDING  OP  SHEET  IRON  179 

give  it  a  more  attractive  appearance.    The  manufacture  of  this 
vessel  is  carried  out  as  follows  :— 

The  flanges  are  lap-welded  as  seamless  rolled  rings.  The 
previously  bordered  and  welded  branches,  of  1,000  m.m. 
diameter,  were  welded  to  the  upper  half-bowl  of  the  vessel, 
having  a  diameter  of  2,000  m.m.  To  the  lower  part  of  the 
vessel,  which  was  welded  in  form  of  a  cone,  were  welded  the 
flanges;  thereafter  the  upper  and  lower  parts  of  the  vessel 
were  welded  together,  and  finally  completed  by  the  welding 
on  of  the  side  flanges  (Figs.  95,  96,  page  174). 

STEEL  PIPES. 

Steel  Pipes  made  at  the  works  of  Messrs.  Stewarts  <£ 
Lloyds,  Limited,  by  the  Ferguson  patent  process,  although 
introduced  only  so  recently  as  1896,  are  already  in  use  to  a 
very  great  extent,  and  they  are  specially  adapted  for  use  as 
conduits  for  water,  sewage,  gas,  or  air,  and  for  any  working 
pressure  up  to  500  Ibs.  per  square  inch.  They  are  usually 
made  in  28-ft.  lengths  and  of  the  following  standard  internal 
diameters  :— 18,  21,  24,  27,  30,  33,  36,  39, 42,  45,  48,  54,  60, 66, 
and  72  ins.  They  are  made  from  acid  or  basic  open  hearth 
steel  plates,  having  an  average  tensile  strength  of  27  tons  per 
square  inch  of  plate  section. 

Compared  with  cast-iron  pipes  of  equal  weight,  Ferguson 
pipes  have  four  and  a  half  times  the  strength,  or,  for  equal 
strength,  are  less  than  a  third  of  the  weight ;  this  effects  a 
considerable  saving  in  first  cost,  freight,  and  handling.  There 
is  also  a  saving  in  cost  of  making  and  maintaining  of  joints, 
owing  to  the  long  lengths  in  which  the  pipes  are  supplied. 
Again,  steel  pipes  are  much  more  effectively  coated  than  cast- 
iron  pipes  by  dipping  hot  in  solution,  and  are  thus  rendered 
much  less  subject  to  corrosion.  Cast-iron  pipes  have  been 
taken  from  the  ground,  after  being  in  use  a  number  of  years, 

N  2 


180  WELDING  AND   CUTTING  METALS 

through  which  daylight  could  not  be  seen  owing  to  an  accumu- 
lation of  corrosion  inside.  Steel  pipes,  on  the  other  hand, 
when  properly  coated,  have  been  found  as  clean  inside  after 
twenty  years  as  when  first  laid. 

Cast-iron  pipes  cannot  resist  the  effects  of  subsidence,  dis- 
tortion, and  shocks  to  which  they  are  frequently  subjected,  as 
pieces  are  apt  to  break  out  of  the  pipe,  leaving  it  open  full 
bore.  This  invariably  results  in  heavy  loss  through  waste  of 
water,  cost  of  repairs  and  relaying,  cessation  of  water  supply, 
and  consequential  damages.  Ferguson  pipes,  on  the  other 
hand,  may  bend  or  flatten,  but  will  not  break.  If  by  reason 
of  excessive  shock  or  pressure  any  failure  should  occur,  it  is 
only  a  crack  of  limited  extent,  usually  causing  little  leakage  or 
damage,  which  can  be  promptly  repaired  temporarily. 

Compared  with  riveted  pipes  of  equal  strength,  Ferguson 
pipes  are  little  more  than  half  of  the  weight  of  single-riveted, 
and  less  than  two-thirds  of  the  weight  of  best  double-riveted 
pipes.  They  remain  tight  even  after  long  transport  by  land 
or  sea,  whereas  riveted  pipes  invariably  leak  badly  before,  and 
more  so  after,  transport,  necessitating  constant  caulking,  with 
its  attendant  evils.  Moreover,  Ferguson  pipes,  as  proved  by 
exhaustive  experiments,  have  33  per  cent,  more  carrying 
capacity  than  riveted  pipes,  and  may  consequently  be  at  least 
12£  per  cent,  less  in  diameter  for  equal  duty. 

The  examples  given  below  show  the  differences  in  cost  for  a 
line  of  Ferguson  pipes,  cast-iron  pipes,  and  riveted  pipes  to  the 
following  specification  : — 

The  pipe  line  to  be  1  mile  long  and  45  ins.  clear 
internal  diameter,  to  stand  a  working  pressure  of  250  Ibs.  per 
square  inch,  with  a  factor  of  safety  of  four  on  the  average 
ultimate  tensile  strength  of  the  pipe  material. 

First  Example. — Cost  of  a  line  of  Ferguson  pipes  45  ins. 
bore  by  f  in.  thick  in  28-ft.  lengths  with  collar  joints  for  lead 


WELDING  OF  SHEET  IEON  181 

and  having  an  average  ultimate  tensile  strength  of  27  tons  per 

square  inch  of  plate  section  : — 

£       s.    d. 
511  tons  of  pipes  and  collars  @  £15  per  ton     .     7,665     0    0 

Carriage  and  cartage  to  site  @  lls.  Sd.  per  ton  298     1  8 

Cutting  and  filling  trench,  say          .         .         .  200     0  0 

Handling  at  site  @  5s.  per  ton          .         .         .  127  15  0 

Jointing  188  pipes  @  60s.  each          .         .         .  564     0  0 


£8,854  16     8 

Second  Example. — Cost  of  a  line  of  cast-iron  pipes  45  ins. 
bore  by  If  in.  thick  in  12-ft.  lengths  with  spigot  and  socket 
joint  for  lead  and  having  an  average  ultimate  tensile  strength 

of  6  tons  per  square  inch  of  pipe  section : — 

£        s.    d. 
1,822  tons  of  pipes  @  £5  10s.  per  ton         .         .  10,021     0     0 

Carriage  and  cartage  to  site  @  lls.  Sd.  per  ton  .  1,062  16  8 

Cutting  and  filling  trench,  say  .         .         .         .  .  200  0  0 

Handling  at  site  @  4s.  per  ton  .         .         .         .  364  8  0 

Jointing  440  pipes  @  80s.  each          /        .         .  660  0  0 

£12,308     4     8 

Third  Example. — Cost  of  a  line  of  double-riveted  steel  pipes 
51  ins.  bore  by  f  in.  thick  in  28-ft.  lengths  with  Kimberley 
collar  joints  for  lead  and  having  an  average  ultimate  tensile 
strength  of  18  tons  per  square  inch  of  plate  section  : — 

£        s.    d, 
963  tons  of  pipes  and  collars  @  £14  per  ton      .  13,482     0     0 

Carriage  and  cartage  to  site  @  lls.  Sd.  per  ton  .  561  15  0 

Cutting  and  filling  trench,  say .  225     0  0 

Handling  at  site  @  4s.  Qd.  per  ton     .      ...  216  13  6 

Jointing  188  pipes  @  60s.  each        ...         .  564     0  0 

£15,049     8     6 


182  WELDING  AND  CUTTING  METALS 

NOTE. — The  riveted  pipes  are  taken  as  51  ins.  bore  to  give 
the  same  carrying  capacity  as  Ferguson  pipes  or  cast-iron 
pipes  45  ins.  bore. 

Copy  of  Letter  received  from  the  Minister  for  Works,  Western 

Australia. 
PUBLIC  WOKKS  DEPARTMENT,  PERTH, 

22nd  May,  1905. 

GENTLEMEN, — In  reply  to  your  letter  of  the  26th  ult., 
regarding  the  Mephan  Ferguson  Locking  Bar  Water  Pipes,  I 
have  the  honour  to  inform  you  that  the  locking  bar  main  of  a 
length  of  over  350  miles  has  now  been  carrying  water  for 
about  three  years  without  a  single  failure  in  any  of  the  lock- 
ing bar  joints,  although  under  a  pressure  as  high  as  500  ft. 
The  lead  joints  joining  the  several  lengths  of  locking  bar  pipe 
to  each  other  occasionally  leak  and  have  to  be  caulked,  but 
this  has  nothing  to  do  with  the  class  of  pipe  used,  as  the  same 
trouble  would  be  experienced  with  either  a  welded  or  riveted 
pipe.  As  regards  the  locking  bar  joints  themselves,  prac- 
tically no  trouble  has  been  experienced  with  these,  and,  but 
for  the  necessity  of  attending  to  the  lead  joints,  not  more 
than  about  three  men  would  be  required  to  patrol  the  whole 
line. 

I  have  the  honour  to  be,  Gentlemen, 
Your  obedient  servant, 

(Sgd.)        W.  D.  JOHNSON, 

Minister  for  Works. 
Messrs.  Stewarts  &  Lloyds,  Limited, 
Glasgow. 

LIFE  OF  STEEL  PIPE  VERSUS  CAST-IRON. 

The  question  of  the  life  of  steel  pipes  versus  cast-iron  is  one 
which  has  long  been  exercising  the  minds  of  engineers.  As 


WELDING  OF  SHEET  IRON  183 

it  is  not  practicable  to  sit  down  and  wait  for  the  necessary 
time  (which  really  means  the  passing  of  a  generation)  to 
elapse  to  prove  beyond  a  doubt  that  the  former  is  equal  in  life 
to  the  latter,  the  next  best  thing  is  to  show,  by  what  has  been 
accomplished,  what  can  reasonably  be  expected.  There  is  no 
doubt  that  the  life  of  a  steel  pipe  mainly  depends  upon  the 
coating,  and,  given  a  good  covering,  a  steel  pipe  will,  without 
doubt,  equal  in  life  that  of  cast  iron.  This  coating  is  com- 
posed of  a  good  mixture  of  Trinidad  asphaltum  and  tar,  and 
has  proved  to  be  most  efficacious. 

Since  the  Ferguson  pipe  was  invented  about  eight  years 
ago,   the   following,  among   other  mains,  have  been  manu- 
factured. 
In  South  Australia  : — 

8,  12,  31,  and  8  miles  respectively  of  pipes  ranging  from 
15  ins.  to  26  ins.  in  diameter,  test  pressure  to  300  Ibs. 

West  Australia : — 

350  miles  30  ins.  diameter  for  the  Coolgardie  water  scheme, 
test  pressure  to  400  Ibs. 

New  South  Wales : — 

13  miles  32  ins.  diameter,  test  pressure  to  300  Ibs. 

South  Africa; — 

12  miles  of  21  ins.  diameter  pipes  for  the  Premier  Diamond 
Mines,  tested  to  the  following  pressures :  J  in.  thick  to 
300,  -f^  in.  thick  to  350,  |  in.  thick  to  450,  T7F  in.  thick 
to  600  Ibs.  per  square  inch  ; 

2  miles  30  ins.  diameter  by  T5Q  in.  for  Durban  Corpora- 
tion ; 

6  miles  30  ins.  diameter  by  ^  in.  for  Durban  Corpora- 
tion. 
England  and  Wales  • — 

13  miles  ranging  from  21  ins.  to  36  ins.  diameter  for  the 


184  WELDING  AND  CUTTING  METALS 

South  Staffordshire  Mond  Gas  Company,  test  pressure 
to  300  Ibs. ; 
8J  miles  of  pipes  ranging  from  21  ins.  to  48  ins.  diameter 

for  the  Western  Valleys  Sewerage  Board  ; 
1,500  ft.  86  ins.  diameter  by  J  in.  for  Conway  Hydro- 
Electric  Power  Main. 
New  Zealand : — 

14  miles  24  ins.  and  27  ins.  diameter  for  Auckland. 
India : — 

4,350  ft.  24  ins.  diameter  by  T3g  in.  for  Benares  Munici- 
pality ; 

3  miles  24  ins.  diameter  bjr  ^  in.  for  Jubbulpore  Water- 
works ; 

1,680  ft.  18,  24,  and  33  ins.  diameter  for  Bombay  Munici- 
pality. 

The  pipes  supplied  for  the  South  Staffordshire  Mond  Gas  Com- 
pany are  being  laid  in  a  part  of  the  country  which  is  the  very 
worst  for  steel  pipes.  Besides  containing  sulphur  and  other 
chemical  properties,  which  are  most  dangerous  to  the  life  of 
steel,  the  land  is  subject  to  subsidences.  It  was  a  matter  of 
great  concern  to  the  engineer  how  best  to  protect  the  pipes 
against  such  enemies,  and  after  much  thought  and  experi- 
menting he  decided  upon  having  the  pipes  coated  once  with 
asphaltum,  then  wrapped  carefully  round  with  Hessian  or 
canvas,  and  afterwards  a  further  coating  of  asphaltum  applied 
on  top  of  this.  The  result  has  been  to  produce  a  coating  which 
is  of  great  thickness,  and  adheres  tenaciously  to  the  pipes, 
and  there  is  no  question  but  it  must  go  far  to  remove  any 
trace  of  doubt  as  to  the  life  of  the  pipes  in  this  treacherous 
district. 

The  following  correspondence  confirms  our  contention  that 
the  life  of  wrought-iron  pipes  is  equal  to  that  of  cast-iron,  so 
far  as  this  can  at  present  be  proved :— 


WELDING  OF  SHEET  IEON  185 

DEPARTMENT  OF  PUBLIC  WORKS,  MELBOURNE, 

25£/i  February,  1902. 

Mr.  Mephan  Ferguson. 

SIR, — With  reference  to  the  life  of  wrought-iron  or  steel 
pipes,  the  fact  is  that  anticipations  have  been  so  much  exceeded, 
and  dismal  prognostications  upset,  that  I  am  not  yet  able  to 
fix  a  period  as  the  limit  of  their  durability. 

It  now  seems  almost  that,  given  the  conditions — (a)  sound, 
well-selected  plates,  free  from  rust ;  (b)  honest  workmanship ; 
(c)  perfect  coating  with  refined  Trinidad  asphaltum,  or  other 
equally  efficacious  envelope ;  (d)  care  in  transit  and  laying  so 
as  to  avoid  abrasion  of  coating  or  the  proper  treatment  of 
unavoidable  abrasions — the  life  of  wrought-iron  pipes  may 
equal  that  of  cast-iron. 

When  I  introduced  wrought-iron  pipes  into  Australia  for 
water  supply  purposes,  it  was  on  the  basis  of  Californian 
practice,  and  notably  as  carried  out  by  Mr.  Schussler,  engi- 
neer of  the  Spring  Vale  (San  Francisco)  Waterworks,  who 
at  that  date  had  nearly  twenty  years'  experience  of  the  system, 
with  the  result  that  whenever  opened  up  the  pipes  were  found 
to  be  in  as  good  condition  as  when  laid,  and,  with  an  added 
eighteen  years,  I  am  aware  that  the  same  condition  prevails. 
Although  at  first  I  was  rather  sceptical  as  to  a  very  extended 
life  for  them,  I  was  able  to  demonstrate  that,  from  a  financial 
point  of  view,  if  wrought-iron  pipes  continued  to  be  so  effec- 
tive in  the  Melbourne  water  supply  system  for  fourteen 
years,  and  were  then  altogether  abandoned,  there  would  be  an 
actual  monetary  gain  at  the  then  relative  prices  for  cast  iron 
and  wrought  iron,  which  made  a  difference  of  over  50  per  cent, 
in  favour  of  the  latter. 

But  eighteen  years  have  now  elapsed,  and  it  can  be  said  of 
our  original  wrought-iron  main,  one  of  7  miles  long  and 


186  WELDING  AND   CUTTING  METALS 

30  ins.  diameter,  that,  as  is  also  Mr.  Schussler's  experience 
in  America,  it  is  as  sound  in  every  particular  as  when  laid 
down,  and  I  see  no  reason  why  it  should  not  be  found  as  sound 
fifty  years  hence.  I  find  that,  before  giving  up  the  Melbourne 
water  supply  in  1890,  I  laid  wrought-iron  pipes  as  follows : — 


DIAMETER. 

LENGTH. 

DIAMETER. 

LENGTH. 

ins. 

miles,   chains. 

ins. 

miles,    chains. 

53 

3         76 

30 

14         68 

50 

5         36 

24 

7         41 

32 

20         40 

18 

5         70 

or  say  58  miles.  Excepting  in  the  case  of  a  few  pipes  laid 
through  bad  ground  in  South  Melbourne,  and  in  respect  of 
which  it  was  afterwards  found  that  there  had  been  careless- 
ness in  handling,  there  had  been  a  complete  absence  of  failure, 
and  of  the  whole  of  them,  as  of  our  initial  main,  it  may  be 
said  that  they  continue  to  be  so  sound,  that  no  line  is  afforded 
from  which  to  predict  when  they  will  be  otherwise. 

I  continue  to  be,  I  assure  you,  quite  satisfied  with  my  action 
in  successfully  combating  doubt  and  opposition  to  the  adoption 
of  wrought  iron  for  large  water  mains. 

Very  truly  yours, 

(Sgd.)  W.  DAVIDSON, 

Inspector-General  of  Public  Works,  Victoria. 

DEPARTMENT  OF  PUBLIC  WORKS,  MELBOURNE, 

I&th  May,  1902. 

SIR, — In  extension  of  my  letter  dated  25th  February,  on 
the  subject  of  the  life  of  wrought-iron  pipes,  I  cannot  now 
help  apprising  you  of  the  great  pleasure  and  satisfaction  I 
have  just  received  from  the  inspection  of  a  length  of  the 
South  Melbourne  24-in.  wrought-iron  main,  the  pipes  for 
which,  you  will  remember,  you  manufactured.  The  main 
crosses  from  Preston  reservoir  to  Brunswick,  and  thence 
down  the  Sydney  Koad,  and  via  Queen's  Bridge  into  the  city 


WELDING  OF  SHEET  IEON  187 

of  South  Melbourne.  It  is,  I  think,  about  10  miles  long.  The 
pipes  are  of  the  original  pattern  of  J-in.  plate,  with  longitu- 
dinal double-riveted  and  transverse  single-riveted  seams  in 
28-ft.  lengths,  fitted  with  spigots  and  faucets.  The  M.  and 
M.  Board,  within  the  past  week  or  so,  made  some  alterations. 
in  this  main  on  the  South  Melbourne  side  of  the  bridge,  which 
necessitated  the  cutting  out  of  a  length  of  24-in.  pipe,  to  which 
had  been  attached  a  cast-iron  12-in.  branch,  with  sluice  valve, 
etc.  This  is  the  pipe  which  I  at  once  took  an  opportunity  of 
inspecting. 

It  was  laid  early  in  1887  in  ground  that  is  the  most  unfavour- 
able of  any  kin  the  Melbourne  district  to  the  preservation  of 
ferruginous  material.  Inside,  the  pipe  is  now  as  if  it  had  just 
come  out  of  your  works,  so  perfect  and  japan-like  is  the  coat- 
ing, and,  making  allowance  for  the  adhering  clay,  the  same 
may  be  said  of  the  outside,  excepting  that  in  cutting  out  rivets 
(the  pipe  appears  to  have  been  taken  out  in  sections),  and  in 
the  handling  and  cartage,  portions  of  the  exterior  coating  have 
been  knocked  off.  This,  for  the  purpose  of  my  examination,  I 
found  to  be  rather  an  advantage,  as  it  afforded  me  a  welcome 
opportunity  for  examining  the  plates  in  several  places.  These 
are  in  perfect  order,  and  considering  the  absence  of  change  in 
practically  sixteen  years  of  service,  I  see  no  reason  why  the  same 
condition  should  not  prevail  for  sixteen  years  longer,  or,  for  the 
matter  of  that,  for  sixty  years  or  longer — indefinitely.  Where 
no  change  has  taken  place  it  is  certainly  warrantable  to  assume 
that,  under  a  continuation  of  the  like  conditions,  none  will  take 
place.  Not  the  least  source  of  my  gratification,  having  first 
become  satisfied  as  to  the  stability  and  certain  longevity  of 
this  main,  is  in  the  splendid  condition  of  the  interior  of  the 
pipe.  Its  perimeter  is  perfect  without  signs  of  incrustation, 
obstruction,  or  deposit.  This  is  the  more  remarkable  from 
the  fact  that,  in  an  equal  period,  a  cast-iron  pipe  of  24  ins. 


188  WELDING  AND   CUTTING  METALS 

diameter  would  have  lost  at  least  1  in.,  and  more  probably 
2  ins.  of  section,  from  incrustation.  The  cast-iron  branch, 
which  had  been  connected  to  this  wrought-iron  pipe,  with  its 
valve,  was  heavily  covered  with  material  adhering  to  the  inner 
surfaces  in  the  form  of  nodules,  and  consisting  of  oxide  of  iron 
and  earthy  matter  attracted  to  it.  This  deposit  or  incrustation 
is  peculiar  to  all  cast-iron  pipes,  large  and  small,  in  the  Mel- 
bourne water  supply  system.  Its  rate  of  growth  is  equal  to  the 
complete  filling  up  of  a  4-in.  pipe  in  from  fifteen  to  eighteen 
years.  The  coating  of  the  wrought-iron  pipes,  as  used  in  the 
Yan  Yean,  is  now  demonstrated  as  being  absolutely  impervious 
to  incrustation,  the  initial  effort  in  which  must  be  from  the 
iron  and  establishes  the  impermeability  of  the  Trinidad 
asphaltum  process.  Altogether  the  result  is  so  pleasing  to 
me,  although  I  have  now  nothing  to  do  with  water  supply 
affairs,  that  I  cannot  refrain  from  expressing  it  to  you,  who 
were  so  closely  associated  with  my  first  efforts  in  introducing 
wrought-iron  pipes,  and  indeed  to  ask  you  to  share  my  feelings 
of  satisfaction,  and,  in  doing  so,  to  authorise  you  to  make  any 
use  of  this  note  you  see  fit. 

Very  truly  yours, 
(Sgd.)     WILLIAM  DAVIDSON, 
Inspector- General  of  Public  Works,  Victoria. 

EELATIVE  CORROSION  OF  WROUGHT  IRON,  SOFT  STEEL,  AND 
NICKEL  STEEL. 

{Paper  read  by  Professor  Henry  M.  Howe  at  the  International 

Congress  on  Testing  Materials  of  Construction  (under  the 

auspices  of  the  Paris  Exposition,  1900). 

The  facts  presented  were  based  on  the  determination  of  the 

loss  of  weight  by  oxidation  of  several  plates  of  wrought  iron, 

soft  steel,  3  per  cent,  nickel  steel,  and  26  per  cent,  nickel  steel, 


WELDING  OF   SHEET  IEON  189 

after  an  exposure  to  sea  water,  river  water,  and  also  to  the 
weather,  for  two  periods  of  about  one  year  each.  Each  of 
the  plates  was  about  24  ins.  long,  16  ins.  wide,  and  J-  in. 
thick,  the  total  weight  of  all  the  plates  was  2,597  Ibs.,  and  the 
total  area  exposed  was  928  square  feet.  Professor  Howe  stated 
that  the  scale  of  these  requirements  was  therefore  not  only 
much  larger  than  that  of  any  previous  experiments  of  which 
he  knew,  but  also  larger  than  that  of  all  previous  experiments 
taken  collectively.  His  paper  includes  tables  and  compari- 
sons of  all  previous  accessible  reliable  investigations  on  this 
subject. 

Professor  Howe  sums  up  the  results  of  his  experiments  in 
the  following  table : — 

Relative  Corrosion  of  Soft  Steel,   Wrought  Iron,  and 
Nickel  Steel. 

(Wrought  iron  taken  as  a  standard.) 

Sea        Fresh 
Water.     Water.  Weather.  Average. 

Wrought  iron    .         .  .100  100  100  100 

Soft  steel  .        .        .  .114  94  103  103 

3  per  cent,  nickel  steel  .       83  80  67  77 

26  per  cent,  nickel  steel  .       32  32  30  31 

He  therefore  found  that  soft  steel  corroded  less  than 
wrought  iron  in  fresh  water,  but  more  than  wrought  iron  in 
sea  water;  the  difference,  though  always  moderate,  was  in 
each  case  sufficiently  constant  to  raise  a  considerable  presiimp- 
tion  that  it  was  a  real,  and  not  merely  an  apparent,  one.  In 
Krupp's  very  important  experiments  the  opposite  results  were 
obtained,  for  soft  steel  corroded  much  less  than  wrought  iron 
in  sea  water ;  and  here,  too,  the  difference  was  so  constant  as 
to  raise  a  considerable  presumption  that  it  was  real,  and  not 
merely  apparent. 


190  WELDING  AND  CUTTING  METALS 

Professor  Howe  draws  two  inferences  :— 

1.  That  the  difference  in   the   rate   of   corrosion   between 
wrought  iron  and  soft  steel  is  rarely  enough  to  be  of  great 
moment,  except  perhaps  in  marine  boilers. 

2.  That  the  ratio  of  the  corrosion  of  a  given  soft  steel  to 
that  of   a  given  wrought  iron  may  vary  greatly   with   the 
conditions  of  exposure. 

He  suggests  two  chief  causes  for  the  apparent  discrepancies 
between  the  results  not  only  of  different  observers,  but  even 
of  the  same  observer : — 

1.  The  quasi-accidental  variations,  individual  peculiarities, 
-etc. 

2.  That  the  susceptibility  to  corrosion  of  soft  steel,  taken  as 
a  whole,  does  differ  somewhat  from  that  of  wrought  iron  taken 
as  a  whole ;  but  that  this  difference  is  of  such  a  nature  that 
wrought  iron,  as  a  class,  corrodes,  on  an  average,  faster  than 
soft  steel  under  certain  conditions,  but  slower  than  soft  steel 
under  others. 

He  referred  to  the  strong  and  wide-spread  belief,  at  least  in 
the  United  States,  that  soft  steel  corrodes  much  more  rapidly 
than  wrought  iron ;  and  stated  that  this  belief  has  greatly 
retarded  the  introduction  of  soft  steel  for  tubes  and  other  pur- 
poses in  which  oxidation  is  a  matter  of  vital  importance ;  and 
stated  that,  having  before  him  the  results  of  such  extensive 
experiments  indicating  the  reverse  of  this  belief,  he  was  led  to 
study  the  cause  of  the  discrepancy. 

He  looks  upon  the  cinder  of  wrought  iron,  and  the  cementite 
of  soft  steel,  as  offering  a  protection  to  the  pure  iron  or  ferrite. 
The  particles  of  ferrite  on  the  surface  are,  of  course,  in  each 
case,  oxidised  at  once,  but  it  may  be  possible  that  the 
mechanical  protection  of  the  flakes  of  cinder  in  the  wrought 
iron  increases  with  time,  much  more  than  the  flakes  of 
-cementite  of  soft  steel,  so  that  it  is  quite  possible  that, 


WELDING  OF  SHEET  IEON  191 

though  wrought  iron  and  soft  steel  corrode  at  the  same  rate 
initially,  yet  later  the  wrought  iron  should  oxidise  much  less 
than  soft  steel.  He  stated  that,  fortunately,  data  for  testing 
this  hypothesis  were  at  hand,  for,  in  his  own  experiments  and 
in  another  very  extensive  series,  the  oxidation  of  soft  steel  and 
of  wrought  iron,  for  each  of  two  successive  long  periods,  was 
given.  Comparing  these,  he  does  not  find  that  the  oxidation 
of  the  soft  steel  accelerates  relatively  to  that  of  wrought  iron 
as  the  period  of  exposure  continues.  The  hypothesis  is  there- 
fore weakened,  and  he  has  hence  concluded  to  continue  his 
experiments  by  re-exposing  all  the  plates,  and  he  hopes  to 
reweigh  and  report  on  them  again  after  a  further  period  of 
several  years. 

Eeferring  finally  to  the  nickel  steels,  he  stated  that  the 
above  table  showed  that,  on  a  general  average,  the  3  per  cent, 
nickel  steel  corroded  77  per  cent,  as  fast  as  wrought  iron, 
and  the  26  per  cent,  nickel  steel  about  one-third  as  fast. 
The  superiority  of  the  3  per  cent,  nickel  steel,  though  decided, 
is  hardly  enough  to  weigh  heavily  in  determining  its  introduc- 
tion. The  26  per  cent,  nickel  steel,  while  having  an  enormous 
advantage  over  wrought  iron  and  soft  steel  as  regards  corrosion, 
can  still  not  be  classed  as  a  non-corroding  metal  under  common 
conditions,  but  simply  as  a  slowly  corroding  one. 


CHAPTEK  VI 

WELDING    APPLIED    TO    STEAM    BOILERS 

General — Welding  Instead  of  Eiveting — Advantages  and  Disadvantages 
of  Welded  Boiler  Joints — Difficulties  of  Eiveted  Joints — Repairs  on 
Steam  Boilers:  Cracks — Locating  the  Cracks — Strength  of  Eiveted 
Joints  —  Cost  of  Eiveted  Seams — Autogenous  Welding  —  Electric 
Welding  —  Hydrogen  Welding  —  Acetylene  -  Dissous  Welding  — 
Repairs  on  Marine  Boilers  :  Outside  Corrosion — Internal  Corrosion 
— Cracks — Autogenous  Welding — Electric  Welding — German  Steam 
Users  Association — British  Steam  Users  Association — Application 
of  Compressed  Gases  to  Welding — Defects  of  Welds — Welding  of 
Tanks — Eelative  Cost  of  Eiveting  and  Acetylene  Welding — Keeping 
Down  the  Heap. 

GENERAL. 

IN  1863  an  article  appeared  in  the  Mechanics'  Magazine 
urging  that  boiler  seams  should  be  welded  instead  of  riveted, 
and  stating  that  almost  the  only  difference  between  the  seam 
then  in  vogue  and  that  of  a  hundred  years  before  was  the  use 
of  a  contrivance  for  finishing  the  rivet  head. 

The  rings  which  form  the  cylindrical  shell  of  the  boiler 
are  curved  from  flat  plates,  and  must  be  joined  at  the  edges 
and  at  their  ends.  The  requisites  of  such  joints  are  : — 

1.  Strength  to  resist  the  strain  from  internal  pressure. 

2.  Tightness  against   leakage  of    water  or  steam,  with  a 
construction  which  shall  not  be  too  costly. 

3.  Ability  to  withstand  heat. 

4.  Ability  to  undergo  changes  of  shape  from  expansions  and 
contractions  without  injury  to  the  metal. 

The  two  edges  of  the  plate  which  are  to   be  joined  are 


WELDING  APPLIED  TO  STEAM  BOILERS  193 

arranged  so  as  to  lap  over  each  other  to  be  secured  together, 
and  this  attaching  can  be  done  by  welding. 

Bolting  with  a  thread  and  nut  will  not  meet  the  require- 
ment of  tightness  against  leakage  unless  the  joint  surfaces  are 
planed  and  finished,  and  the  boltholes  seamed,  and  the  bolts 
turned.  This  is  prohibitory  from  its  cost,  and  even  if  this  were 
not  a  barrier,  the  friction  of  the  nut  so  reduces  the  clamping 
power  of  the  screw  bolt  that  it  would  make  a  much  weaker 
joint  than  is  secured  by  the  other  plans. 

Welding  of  boiler  plate  to  make  the  joint  with  itself  or  other 
parts  of  the  shell  offers  many  advantages. 

The  welding  property  of  wrought  iron  and  ductile  steel 
enables  them  to  unite  at  clean  surfaces  when  pressed  together 
with  sufficient  force  in  a  state  of  sufficient  plasticity  from 
heat.  The  presence  of  oxide  of  iron,  or  dirt,  or  cinder  between 
the  contact  surfaces  or  inadequate  pressure  to  unite  the  surfaces 
together  will  prevent  a  satisfactory  weld.  When  satisfactory  the 
weld  may  be  expected  to  be  as  strong  as  the  rest  of  the  metal. 

Welding  of  plate  is  done  by  lapping  the  two  edges  over  for 
two  or  three  inches,  heating  the  lap  to  a  welding  heat  on  both 
sides  by  a  flame  or  jet  of  gas  free  from  sulphur  or  other 
oxidising  tendencies,  and  then  bringing  the  lapped  surfaces 
together  either  by  the  force  of  percussive  hammer  or  sledge 
blows  or  by  steady  pressure  of  cams  or  roller  presses.  Some 
fluxing  material,  like  borax,  which  will  make  a  fluid  glass  with 
oxide  of  iron,  may  be  used  as  a  protection  for  the  contact 
surfaces,  so  as  to  prevent  oxidation  from  exposure  to  air,  with 
the  expectation  that  it  will  be  expelled  from  the  joint  by  the 
welding  pressure,  and  carry  with  it  everything  which  would 
interfere  with  good  welding. 

Advantages  of  welded  boiler  joints  : — 

1.  It  makes  the  joint  as  strong  as  the  rest  of  the  plate,  or 
nearly  so. 

w.  o 


194  WELDING  AND   CUTTING  METALS 

2.  The   plate  is  no  thicker  at  the    joints  than  elsewhere. 
This  avoidance  of  a  lap  keeps  the  tensile  strain  from  internal 
pressure  always  in  the  axis  of  the  plate  and  without  a  tendency 
to  flux  at  the  lap  or  joint. 

3.  Double  or  extra  thickness  is  avoided  at  laps  or  joints. 
The  plate  gets  unnecessarily  hot  at  multiple  thicknesses,  and 
oxidation  is  more  rapid  there. 

4.  No  rivets  are  required,  which  makes  the  boiler  lighter 
and  less  liable  to  leak. 

5.  A   good   welded   seam   is  watertight,    and   requires    no 
caulking. 

Disadvantages  of  welded  seam  in  boilers  :— 

1.  It  cannot  be  inspected  for  its  satisfactory  quality,  unless 
it  is  so  bad  as  to  allow  water  to  leak  through  it  under  pressure. 
But  it  may  be  watertight  and  yet  be  far  from  having  full 
strength.    Wh ile  a  test  by  hammer  taps  to  observe  the  resonance 
of  the  metal  at  the  joint  will  reveal  much  to  the  practised  ear, 
it  lacks  the  convincing  force  of  an  inspection  of  each   single 
rivet  in  a  riveted  seam. 

2.  Welded  joints  in  large  shells  can  only  be  obtained  from 
a  few  firms  with    facilities  and  experience    for    such    work. 
This  has  some  effect  upon  the  cost  of  such  joints.     But  when 
a  satisfactorily  welded  seam  can  be  obtained  it  makes  an  ideal 
joint. 

In  cylinders  with  closed  ends  the  last  seam  must  be  riveted 
even  if  the  others  are  welded.  The  exception  is  where  the 
head  is  flanged  outward,  or  is  convex  inward  so  as  to  bring 
the  closing  joint  outside  the  shell. 

Riveted  joints,  with  their  consequent  double  thickness  of 
metal,  in  parts  exposed  to  the  fire,  give  rise  to  serious  diffi- 
culties. Being  the  weakest  parts  of  the  structure,  they  con- 
centrate upon  themselves  all  strains  of  unequal  expansion, 
giving  rise  to  frequent  leaks,  and  not  rarely  to  actual  rupture. 


WELDING  APPLIED  TO  STEAM  BOILEES  195 

The  joints  between  tubes  and  tube  sheets  also  give  much 
trouble  when  exposed  to  the  direct  fire,  as  in  locomotive 
and  tubular  boilers.  This  difficulty  is  partly  overcome  by 
welding. 

KEPAIRS  ON  STEAM  BOILERS. 

It  is  customary  when  a  slight  crack  appears  in  a  boiler  plate 
to  repair  the  leak  by  drilling  small  holes  at  the  ends  of  the 
crack  in  order  to  prevent  it  from  spreading  any  further,  and 
then  caulking  the  crack  and  covering  it  with  a  patch.  This 
kind  of  repair  can  be  easily  done  by  any  good  boiler-maker, 
but  there  is  one  point  which  should  not  be  overlooked  :  that 
it  is  absolutely  necessary  that  the  small  holes  which  are 
drilled  at  the  ends  of  the  crack  be  located  at  the  extreme  ends 
of  the  crack,  and  not  merely  near  the  ends.  It  is  often  difficult 
to  tell  exactly  how  far  the  crack  extends,  and  therefore  these 
holes  are  sometimes  located  near  the  end  instead  of  at  the  end. 
In  this  case,  continued  use  of  the  boiler  will  develop  the  crack 
beyond  the  holes,  and  the  trouble  must  be  repaired  again. 

While  ordinary  careful  investigation  may  fail  to  locate  the 
ends  of  the  crack,  yet  there  is  a  simple  way  in  which  this  may 
be  safely  done.  First  rub  the  plate  in  the  vicinity  of  the 
crack  with  oil ;  wipe  the  oil  off,  and  cover  the  plate  with 
chalk.  The  oil  which  has  penetrated  the  crack  will  then  be 
exuded  and  show  plainly  the  extent  of  the  crack  in  the  chalk, 
whereupon  the  holes  may  be  located  in  their  proper  places, 
and  either  a  hard  or  a  soft  patch  may  be  applied,  according 
to  the  position  of  the  damaged  plate. 

Eiveted  joints  have  always  been  an  expensive  and  trouble- 
some part  of  a  boiler  to  construct.  An  ideal  boiler  shell 
would  be  one  in  which  there  were  no  seams,  so  that  the  entire 
shell  would  be  one  homogeneous  piece  of  metal,  all  parts  of 
which  were  equally  strong.  A  riveted  joint  must  always  be 

o  2 


196  WELDING  AND   CUTTING  METALS 

weaker  than  the  solid  plate  unless  the  plate  at  the  joint  is 
up-set  so  that  its  thickness  is  greater  than  the  thickness  of 
the  rest  of  the  shell,  an  operation  which,  for  practical  reasons, 
is  impossible.  The  best-designed  riveted  joints  rarely  have 
more  than  90  per  cent,  of  the  strength  of  the  plate  which 
they  join,  while  the  ordinary  double-riveted  lap  and  butt  joints 
have  a  very  much  less  efficiency,  ranging  from  65  to  85  per 
cent.  Furthermore,  it  takes  skilled  labour  and  expensive 
machinery  to  lay  out  the  seams,  and  punch  or  drill  the  rivet 
holes,  and  drive  the  rivets,  and,  even  with  the  best  work, 
there  is  apt  to  be  trouble  in  making  the  joints  steamtight,  for 
the  rivets  must  be  thoroughly  up-set  in  the  holes  and  the 
edges  of  the  seams  carefully  caulked. 

The  Boiler-maker  estimates  in  the  case  of  a  72-in.  by 
18-ft.  horizontal  tubular  boiler,  built  to  withstand  a  pressure 
of  125  Ibs.  per  square  inch,  that  the  total  cost  of  labour  and 
material  used  in  the  boiler  would  be  about  $561,  of  which  80 
per  cent,  is  the  cost  of  material  and  20  per  cent,  is  the  cost  of 
labour.  Of  this  amount  the  cost  of  labour  on  the  riveted 
joints  alone — that  is,  of  laying  out  the  rivet  holes,  punching, 
riveting,  etc. — is  19  per  cent,  of  the  cost  of  labour  and  3'7  per 
cent,  of  the  total  cost  of  the  boiler.  The  additional  material — 
that  is,  butt  straps  or  laps  and  rivets — amounts  to  5  per  cent, 
of  the  cost  of  material  and  3*8  per  cent,  of  the  total  cost  of 
the  boiler.  Therefore  the  cost  of  the  riveted  joints  alone  is 
about  8  per  cent,  of  the  total  cost  of  the  boiler.  This  is 
assuming  that  the  longitudinal  joint  is  a  double-riveted  butt 
joint,  and  that  the  holes  are  punched  and  all  rivets  driven  on 
the  machine.  If  a  stronger  joint  were  used,  or  if  the  holes 
were  drilled  or  the  rivets  driven  by  hand,  the  cost  of  the 
riveted  joints  would  be  increased. 

The  only  possible  substitute  for  riveting  seems  to  be  some 
form  of  welding  in  which  the  metal  itself  is  structurally 


WELDING  APPLIED   TO   STEAM  BOILEKS  197 

united  in  such  a  manner  that  the  finished  product  forms  one 
homogeneous  piece  of  uniform  quality  and  properties  through- 
out. Furthermore,  in  order  for  such  a  system  to  be  of  any 
practical  use,  the  tensile  strength  of  the  welded  joint  must  be 
as  great  as  or  greater  than  that  of  a  riveted  joint,  and  the  cost 
of  doing  the  work,  including  the  fixed  charges  on  the  apparatus, 
must  not  be  greater  than  the  cost  of  riveting ;  that  is,  it  must 
be  less  than  8  or  10  per  cent,  of  the  total  cost  of  the  boiler. 

The  ordinary  methods  of  welding  by  mechanical  means, 
such  as  hammering,  cannot  be  used  in  welding  boiler  shells, 
both  for  practical  reasons  and  because  the  strength  of  a  weld 
made  in  this  manner  is  always  uncertain. 

By  the  autogenous  welding  the  metal  itself  is  raised  to  a 
temperature  sufficiently  high  to  cause  it  to  be  its  own  joining 
material ;  that  is,  the  parts  are  joined  together  by  the  fusion 
of  their  own  substance  without  mechanical  aid.  Such  a 
process  requires  that  only  a  small  area  of  the  metal  in  the 
vicinity  of  the  joint  be  raised  to  a  high  temperature,  and  for 
this  purpose  electricity  was  first  used.  While  the  cost  of 
electricity  for  this  purpose  is  not  excessive,  yet  it  is  rarely 
used,  except  on  castings. 

The  hydrogen  welding  is  successfully  used  on  plates  up  to 
30  m.m.  thickness,  and  it  is  claimed  that  a  joint  of  perhaps 
95  per  cent,  of  the  strength  of  the  metal  can  be  made.  The 
temperature  (2,000°  F.)  obtainable  with  the  hydrogen  blow- 
pipe is,  however,  somewhat  less  than  the  melting  point  of 
mild  steel  (between  2,700  and  2,800°  F.),  so  that  for  thick 
plates  the  heating  must  be  continued  for  some  time,  and 
therefore  the  consumption  of  oxygen  and  hydrogen  rapidly 
increases  with  the  thickness  of  metal  being  welded,  increasing 
the  cost  of  welding. 

A  still  more  recent  development  is  the  use  of  acetylene- 
dissous,  and  this  seems  to  have  been  fairly  successful,  since  a 


198  WELDING  AND   CUTTING  METALS 

very  high  temperature  (3,600°  F.)  can  be  obtained  with  it,  so 
that  plates  up  to  20  m.m.  thickness  can  be  welded  more 
rapidly. 

At  present  the  use  of  autogenous  welding  will  probably  be 
confined  to  repair  work,  for  which  it  seems  particularly  well 
adapted  on  account  of  its  portability.  It  certainly  will  not, 
nor  can  it  be  recommended  to,  be  used  for  welding  seams  of 
large  boilers  or  pressure  tanks  until  it  is  absolutely  known 
that  a  reliable  weld  can  be  made  which  will  be  at  least  85  per 
cent,  as  strong  as  the  metal  itself.  The  results  obtained  are, 
besides,  largely  dependent  on  the  personal  skill  of  the  welder 
both  in  regard  to  the  quality  of  the  work  turned  out  and  the 
speed  at  which  such  welding  can  be  done. 

EEPAIRS  ON  MARINE  BOILERS. 

Nearly  all  waters  contain  foreign  substances  in  greater  or 
less  degree,  and  though  there  may  be  a  small  amount  in  each 
gallon,  they  become  of  importance  where  large  quantities  of 
water  are  evaporated.  Naturally,  when  water  is  evaporated 
and  turned  into  steam,  salts  held  originally  in  solution  must 
become  deposited. 

The  accumulation  of  incrustation  is  of  course  objectionable 
in  every  form  of  boiler,  for,  irrespective  of  the  greater  wear 
and  tear  it  entails,  it  is  the  cause  of  loss  of  efficiency. 

Outside  corrosion  which  is  found  upon  the  surface  of 
the  fire  tube  by  contact  of  the  water  depends  upon  the  boiler 
being  fed  with  bad  water.  Generally  this  corrosion  is  not 
being  properly  considered,  and  it  is  found  that  salt  deposits 
are  formed  upon  the  surface  of  the  plate.  The  plate  is  thus 
in  those  places  exposed  to  a  higher  temperature  than  in  its 
other  parts,  and  it  is  also  being  chemically  acted  upon  by 
the  salt. 

These  corrosions  can  appear  upon  the  whole  surface,  but 


WELDING  APPLIED  TO  MAEINE  BOILEES  199 

generally  they  are  limited  to  a  width  of  10  to  20  m.rn.,  and 
run  along  the  whole  length  of  the  tube  above  the  grate  bars. 
This  is  the  place  where  the  tube  is  exposed  to  the  greatest 
heat,  and  where  therefore  the  salt  deposits  are  most  easily 
formed.  Such  corrosion  is  often  very  deep,  and  the  engineer 
who  only  can  look  over  a  comparatively  small  surface  attaches 
little  importance  to  them ;  besides,  it  is  very  difficult,  if  not 
altogether  impossible,  to  make  a  correct  examination  by 
simply  ocular  inspection. 

In  cases  where  the  corrosion  has  been  freely  exposed  by 
scraping  off  the  salt  deposits,  the  true  nature  and  extent  of 
the  dangerous  state  of  the  tubes  will  be  apparent,  the  cor- 
rosion having  reduced  the  thickness  of  the  plates  to  that  of  a 
few  millimetres.  The  corrosions  which  appear  as  a  straight 
band  along  and  on  both  sides  of  the  tubes  are  very  dangerous, 
being  just  on  those  places  where  an  inspection  or  control  is 
almost  impossible,  and  produce  thereby  a  considerable  reduc- 
tion in  the  safety  of  the  boiler.  For  a  long  time  no  remedy 
could  be  found,  and  it  was  necessary  to  exchange  the  damaged 
tube  for  a  new  one. 

Internal  Corrosion. — Many  and  various  have  been  the 
explanations  offered  for  the  phenomena  of  internal  corrosion 
in  marine  boilers.  Professor  Vivian  B.  Lewes — a  recognised 
authority  on  the  subject  of  marine  boiler  deterioration — states 
that  in  the  presence  of  moisture  carbonic  acid  and  oxygen 
simultaneously  attack  iron  and  steel,  forming  a  thin  layer  of 
carbonate  of  iron.  This  is  a  very  unstable  salt,  which  almost 
immediately  breaks  down  into  iron  oxide  and  ferric  hydrate, 
liberating  the  carbonic  acid,  which,  with  a  further  supply  of 
atmospheric  oxygen,  continues  the  process  of  corrosion  or 
rusting.  This  process  is  further  hastened  by  a  certain  degree 
of  electrolytic  activity  between  the  iron  and  the  electro-negative 
hydrated  iron  oxide.  Inasmuch  as  the  layer  of  oxide,  or,  as 


200  WELDING  AND   CUTTING  METALS 

it  is  commonly  known,  rust,  is  highly  porous,  the  action  pro- 
gresses without  interruption  as  long  as  the  conditions  are 
favourable.  The  above  general  conditions  obtain  when  any 
iron  or  steel  is  exposed  to  the  action  of  oxygen,  carbonic  acid, 
and  moisture. 

Cracks. — The  question  of  the  formation  of  cracks  in  iron 
and  steel  by  heat  stresses  has  been  widely  discussed, 
especially  in  the  case  of  steam  boiler  construction.  There  is 
frequently  doubt  concerning  the  nature  of  the  origin  and  the 
action  of  such  stresses  and  concerning  the  true  reason  for  the 
formation  of  the  cracks.  Lacking  any  other  satisfactory 
explanation,  one  is  easily  inclined  to  ascribe  the  cause  either 
to  the  material  and  its  chemical  composition  or  to  the  design 
of  the  boiler,  or  perhaps  to  its  construction.  Without  doubt 
one  or  the  other  of  these  reasons  enters  into  a  great  many 
cases  in  a  greater  or  less  degree,  but  it  is  also  certain  that 
cracks  have  been  found  where  no  known  reason  will  suffice 
for  an  explanation,  where  material  has  failed  which  fulfils 
all  specifications,  where  the  design  of  the  boiler  is  above 
criticism,  and  where  its  construction  has  been  proved  excellent. 

The  furnaces  and  combustion  chambers  of  boilers  suffer 
generally  through  overheating,  caused  principally  through 
the  presence  of  scale,  the  lavish  use  of  oil,  or  shortness  of 
water. 

The  special  interest  attached  to  the  application  of  auto- 
genous welding  to  repairs  in  marine  boilers  is  based  upon 
the  following  reasons  : — 

1.  Repairs  may  be  carried  out  at  once,  avoiding  thereby 
extra  delay  in  harbour. 

2.  Defects,    caused,    for    instance,    by    corrosion,    leakage, 
cracks,  may  be  repaired  which  otherwise  would  necessitate 
the  replacing  of  the  damaged  pieces  by  new  ones. 

3.  Defects  may  be  repaired  almost   as   soon  as   they  are 


WELDING  APPLIED  TO   MARINE  BOILEES  201 

detected,  and  at  any  place.  A  boiler  which  could  thus  be 
repaired  as  and  when  required  would  naturally  add  to  its 
durability.  Sometimes  it  happens  that  a  boiler  has  to  be 
removed  and  replaced  by  a  new  one  even  after  the  first  break- 
down ;  it  may  now  be  possible  to  repair  it,  saving  thereby 
considerable  expense.  For  instance,  where  the  tube  plates  are 
destroyed  more  or  less  by  corrosion,  it  is  impossible  to  take 
them  out  without  first  removing  the  boiler,  and  it  is  generally 
preferred,  in  such  cases,  to  replace  it  by  a  new  one.  By 
means  of  the  autogenous  welding  it  may  be  possible  to  make 
a  proper  repair. 

4.  It  happens  often  that  the  skin  of  the  shell  is  unevenly 
affected,  particularly  on  old  vessels  ;  it  may  be  rectified,  and 
thus  extend  the  life  of  the  vessel. 

The  following  paper  by  Mr.  Harry  Ruck-Keene,  read  at  the 
Engineering  and  Machinery  Exhibition,  Olympia,  London, 
before  the  members  of  the  Institute  of  Marine  Engineers,  on 
28th  September,  1907,  is  reprinted  here. with  kind  permission 
of  the  said  Institute  and  the  editor  of  The  Marine  Engineer 
and  Naval  Architect  :— 

"  The  repairing  of  boilers  is  a  subject  which  must  always  be 
of  interest  to  marine  engineers,  and  I  propose  in  this  paper  to 
describe  two  processes  of  effecting  repairs,  by  welding  in  place, 
which  have  so  far  given  satisfactory  results,  and  at  the  same 
time  have  effected  repairs  at  probably  less  cost  and  in  many 
cases  in  less  time  than  by  the  ordinary  methods  of  welding. 
These  processes  are  the  oxy-acetylene  and  electric  systems  of 
welding,  whereby  cracks  in  plates  may  be  welded  up  in  place 
patches  may  be  fitted  and  welded  in  place  without  forming 
new  seams,  as  would  be  necessary  if  they  were  riveted,  and 
wasted  plates  and  landing  edges  may  be  built  up  to  their 
required  thicknesses.  Now  the  ordinary  form  of  welding  can 
certainly  not  be  called  a  new  process,  for  though  I  have  been 


202 


WELDING  AND   CUTTING  METALS 


unable  to  find  who  was  the  first  discoverer  of  the  art  of 
welding,  yet  on  referring  to  the  fourth  chapter  of  Genesis  I 
find  that  Tubal  Cain  (who  lived  about  3,950  years  B.C.),  is 
there  described  as  '  an  instructor  of  every  artificer  in  brass 
and  iron,'  and  so  we  may  fairly  conclude  that  the  ordinary 
form  of  welding  was  known  in  those  days.  And  by  the 
ordinary  form  of  welding  in  wrought  iron  or  steel  I  mean 
that  which  consists  of  the  parts  to  be  united  being  heated  to  a 


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PIG.  101. — Eepairs  by  Oxy- Acetylene  Process. 

suitable  temperature  at  which  they  become  plastic,  but  not 
actually  fused,  and  are  then  united  by  hammering,  squeezing 
or  rolling.  Although  the  metal  itself  does  not  become  fused 
at  this  temperature,  yet  it  becomes  rapidly  oxidised,  but  the 
oxide  formed  is  liquid  at  this  temperature,  and  in  properly 
made  welds  it  is  entirely  squeezed  out  from  between  the 
surfaces  to  be  welded.  To  render  the  oxide  still  more  liquid 
and,  therefore,  more  easily  expelled  from  the  weld,  a  flux  of 
white  sand  (silica)  is  sometimes  used  ;  this  forms  with  the 
oxide  a  silicate  of  iron  which  has  a  lower  melting  point  than 
oxide  of  iron,  and  although  when  a  flux  is  used  the  iron  or 


WELDIXG-  APPLIED  TO  MAEINE  BOILEES 


203 


steel  is  probably  less  adhesive  than  it  is  at  the  temperature  at 
which  the  oxide  melts,  yet  the  importance  of  using  every 
means  of  getting  rid  of  the  scale  between  the  surfaces  to  be 
welded  justifies  the  use  of  a  flux  in  most  cases.  But  to  come 
down  from  the  days  of  Tubal  Cain  to  more  modern  times,  it 
was  the  practice  of  several  well-known  firms  when  making 


FIG.  102. — Repairs  by  Oxy- Acetylene  Process. 

iron  boilers  to  weld  the  longitudinal  seams  of  the  shell  plates 
of  boilers  instead  of  riveting  them,  and  in  1874  some  exhaustive 
tests  then  made  proved  the  efficiency  of  these  welded  seams  to 
be  about  70  per  cent,  of  the  solid  plate.  And  I  have  only 
heard  of  one  case  in  which  the  weld  gave  way,  and  that  was 
in  1889,  when  a  boiler,  eight  years  old,  was  subjected  to 
hydraulic  test,  after  undergoing  repairs,  and  the  longitudinal 


204 


WELDING  AND   CUTTING  METALS 


seam  cracked  through  the  weld  for  a  length  of  about  6  ins. 
When  steel  took  the  place  of  iron  in  the  manufacture 
of  boilers  this  practice  of  welding  longitudinal  seams  was 
discontinued.  But  many  firms  still  continue  to  weld  the 
furnaces  to  the  tube  plates  in  steel  boilers  ;  and  it  is  the 
universal  practice  nowadays  to  weld  the  longitudinal  seams  of 
furnaces,  no  matter  whether  they  be  of  the  plain,  corrugated, 
or  ribbed  type.  So  that  it  will  be  seen  that  welding,  though 
decried  by  many  engineers,  is  still  extensively  used  in  the 


FIG.  103.— Eepairs  by  Oxy-Acetylene  Process. 

manufacture  of  boilers.  In  the  oxy-acetylene  and  electric 
processes  of  welding,  though  the  surfaces  of  the  metal  to  be 
welded  are  heated  up  to  practically  the  same  temperature  as 
in  the  ordinary  methods  of  welding,  yet  the  subsequent  ham- 
mering, squeezing,  or  rolling  is  dispensed  with,  except  in  that 
process  of  electric  welding  which  I  propose  to  describe  where 
a  certain  amount  of  hammering  is  still  used  in  making  the 
weld.  For  the  purpose  of  repairing  boilers  by  the  oxy- 
acetylene  process  the  necessary  apparatus  practically  consists 
of  a  steel  cylinder  containing  oxygen  gas  and  another  contain- 
ing dissolved  acetylene,  both  under  pressure,  a  special  blow- 
pipe, flexible  tubes  for  transmitting  the  gases  from  the 


WELDING  APPLIED  TO  MAEINE  BOILEES 


205 


cylinders  to  the  blowpipe,  and  small  bars  or  rods  of  iron 
or  mild  steel  about  -fg  in.  diameter,  which  are  fused  and 
attach  themselves  to  the  parts  to  be  united.  The  oxygen  and 
acetylene  gases  in  these  cylinders  are  led  to  the  blowpipe  by 
means  of  the  before-mentioned  pipes  and  there  ignited  at  the 
nozzle,  the  resultant  flame  giving  out  an  intense  heat. 
Where  plates  are  wasted  away  by  corrosion  or  otherwise,  the 
wasted  parts  are  first  thoroughly  cleansed  to  remove  any  dirt 
or  grease,  and  are  then  heated  to  a  welding  heat  by  means  of 


FIG.  104. — Repairs  on  Main  Boilers  by  Electric  Welding. 

the  flame  from  the  blowpipe ;  the  iron  or  steel  bar  is  in  the 
meantime  held  in  this  flame  until  a  small  portion  at  the  end 
of  the  bar  is  melted  off  and  attached  to  the  part  to  be  repaired, 
and  this  process  is  continued  until  by  the  addition  of  drop 
after  drop  sufficient  metal  has  been  added  to  bring  the  plate 
up  to  its  required  thickness.  When  a  crack  in  a  plate  has  to 
be  welded  up,  the  metal  on  either  side  of  the  crack  is  cut 
away  to  form  a  V-shaped  groove,  and  thus  enable  the  flame  to 
penetrate  to  the  bottom  of  the  crack  and  heat  the  surrounding 
metal  to  the  required  temperature,  metal  being  at  the  same 
time  added  from  the  small  bar  to  fill  up  the  groove,  in  the 
same  way  as  the  wasted  plate  was  built  up.  In  a  similar 


206 


WELDING  AND   CUTTING  METALS 


manner,  by  chamfering  away  the  edges,  two  plates  can  be 
welded  together.  Naturally  in  all  these  cases  great  care  must 
be  taken  to  see  that  each  and  every  piece  of  metal  added 
becomes  firmly  attached  before  adding  more  metal  to  it.  This 
process  has  been  very  satisfactorily  employed  in  this  country 
for  many  purposes,  and  more  especially  for  welding  flanges 
and  branches  on  iron  and  steel  pipes  (which  have  to  withstand 


FIG.  105.— Eepairs  on  Laminated  Tube  Plate  by  Electric  Welding. 

high  pressure),  but  so  far  it  has  been  little  used  for  effecting 
boiler  repairs.  In  Marseilles  and  Genoa  quite  a  considerable 
number  of  boiler  repairs  have,  however,  been  carried  out  in 
the  last  few  years  by  this  process  with  satisfactory  results. 
Among  other  repairs  I  may  mention  those  carried  out  to  two 
marine  boilers,  where  the  bottom  plating  of  the  combustion 
chambers  and  the  lower  part  of  the  combustion  chamber  back 
plating,  and  also  parts  of  the  furnaces  (Jf  in.  thick),  were 
considerably  wasted  by  corrosion.  The  defective  parts  were 
cut  out,  patches  made  to  suit,  and  instead  of  riveting  them  on, 


UNIVERSITY 

OF 


WELDING  APPLIED   TO  MARINE  BOILERS 


207 


they  were  welded  in  place  by  this  process,  thus  avoiding  the 
making  of  additional  riveted  seams  in  the  furnaces  and  com- 
bustion chambers,  which  often  give  so  much  trouble  in  boilers. 


FIG.   106. — Repairs  on  Eurnace  and   Combustion  Chamber  Plating   by 
Electric  Welding. 

The  landing  edges  of  the  lower  part  of  the  back  end  plates  of 
these  boilers  were  also  considerably  wasted,  and  these  were 
made  good  and  built  up  to  their  original  thickness  in  the 
manner  I  have  already  described.  These  repairs  were  carried 
out  under  the  supervision  of  my  colleague  (Mr.  Jones)  at 


208 


WELDING  AND   CUTTING  METALS 


Marseilles,  in  June,  1906,  and  after  twelve  months'  work  they 
were  again  examined  in  July  last  and  found  to  be  quite  satis- 


FIG.  107. — Eepairs  on  Centre  Furnace  by  Electric  Welding. 

factory   and  showing  no  signs  of  leakage.     In  another  case 
eighteen  furnaces  of  the  main  boilers  of  another  vessel  were 


PIG.  108. — Eepairs  of  Cracks  in  Furnace  by  Electric  Welding. 

so  badly  wasted  by  corrosion  on  the  water  side  near  the  line 
of  fire-bars,  that  in  the  ordinary  way  these  furnaces  would 


WELDING  APPLIED  TO  MAEINE  BOILEES 


209 


Lave  had  to  be  renewed,  but  by  this  process  the  wasted  parts 
of  these  furnaces  were  built  up  to  their  required  thicknesses 
by  welding  on  sufficient  metal  piece  by  piece,  thus  saving  the 
time  and  expense  of  renewing  the  furnaces.  In  another  case 
the  furnaces  of  some  other  boilers  were  badly  wasted  and 
cracked,  and  these  were  satisfactorily  welded  up  by  the  same 
process  ;  there  being  in  all  about  one  hundred  cracks  in  the  two 
furnaces  and  the  repairs  taking  about  three  weeks.  Figs.  101 
to  103, 1  think,  explain  these  repairs  better  than  I  can  describe 
them  on  paper.  I  could  cite  many  more  cases,  but  I  think 
those  I  have  mentioned  will  give  some  idea  of  what  can  and 
has  been  done  in  repairing  boilers  by  this  process.  After  the 


FIG.  109. — Eepairs  to  a  Furnace  of  a  Boiler  by  Electric  Welding. 

welding  operation  it  is  usually  considered  better  to  heat  the 
surrounding  plate  by  means  of  the  blowpipe  flame  to  counter- 
act, as  far  as  possible,  the  strains  that  might  be  set  up  by  the 
intense  local  heat.  Naturally,  if  it  were  possible,  it  would  be 
better  to  properly  anneal  the  plate  dealt  with.  This  process 
has  also  been  very  usefully  employed  in  the  cutting  out  of 
defective  and  damaged  plates,  the  flame  from  the  blowpipe 
melting  and  thus  cutting  a  groove  about  T%  in.  wide,  in  much 
w.  P 


210 


WELDING  AND  CUTTING   METALS 


FIG.  110.— 


irs  to  a  Furnace  in  way  of  an  Adamson  Eing  by 
Electric  Welding. 


WELDING  APPLIED  TO  MAEINE  BOILERS 


211 


the  same  way  as  would  be  done  by  a  band  saw,  the  separation 
being  quite  as  cleanly  and  accurately  done  and  in  much  less 
time  than  by  the  ordinary  methods  of  hand  cutting.  The 
following  are  results  of  tests,  made  in  June  last,  from  samples 
taken  from  a  plate  welded  by  the  oxy-acetylene  process,  and 


FIG.  111. — Eepairs  to  Furnace  and   Combustion   Chamber  Plating  by 
Electric  Welding. 

are  the  same  as  those  I  gave  in  a  paper  read  at  the  Engineer- 
ing Conference  of  the  Institution  of  Civil  Engineers  :  — 

OXY-ACETYLENE    WELDING. 


Breadth. 

Thick- 
ness. 

Area. 

Tons, 
Total. 

Tons  per 
Sq.  In. 

Extension  in  4  ins. 
per  cent. 

Ins. 

Ins. 

Ins. 

Not  annealed 
Annealed 

1-5 

1-5 

•62 
•62 

•93 
•93 

22-85 
22-35 

24-5 
24-0 

!?2  1  Solid  Plate. 

00  ) 

Extension  in  8  ins. 

per  cent. 

Not  annealed 

1-5 

•62 

•93 

22-9 

24-6 

28  \  Broke  away 

!  from  the 

Annealed 

1-5 

•63 

•945 

22-1 

23-3 

29  )  weld. 

COLD  BENDS. 

Not  annealed  .         .         .         .         .     1 80C 
Annealed  .         .         ,         .     1SOC 


p  2 


212  WELDING  AND   CUTTING  METALS 

They  show  not  only  the  efficiency  of  the  weld,  but  also  that 
the  ductility  of  the  surrounding  metal  in  way  of  the  weld  has 
not  been  distressed  by  the  intense  local  heat.  It  will  be 
noticed  that  the  tensile  strength  of  the  welded  plate  is  the 
same  as  that  of  the  solid  plate,  the  elongation  per  cent,  is  also 
the  same,  and  the  bend  tests  are  quite  as  good  as  those  which 
might  be  expected  from  the  solid  plate. 

There  are  several  systems  in  use  for  welding  by  electricity 
which  have  been  employed  for  a  number  of  years,  and  are 
used,  among  other  things,  for  welding  tram-rails  in  place,  in 
making  good  blow-holes,  etc.,  in  steel  castings,  and  also  in 
welding  together  pipes,  more  especially  those  for  refrigerating 
plant  which  have  to  withstand  high  pressures.  But  as  with  the 
oxy-acetylene  process,  little  use  has  so  far  been  made  of  these 
processes  in  this  country  for  repairing  boilers.  In  the  last 
few  years,  however,  electric  welding  has  been  used  abroad  for 
this  purpose,  more  especially  at  Gothenburg  in  Sweden,  where 
quite  a  number  of  boiler  repairs  have  been  carried  out  by  this 
process.  The  process  there  employed  is  somewhat  similar  to 
the  oxy-acetylene  process,  but  the  heat  is  generated  by  the 
electric  arc  instead  of  by  the  flame  from  the  blowpipe.  The 
plant  there  used  consists  of  a  barge  containing  two  dynamos 
of  45  kilowatt  power  driven  by  a  steam  engine,  and  a  third 
dynamo  of  3  kilowatt  power  for  feeding  the  magnets.  The 
voltage  used  is  between  80  and  120.  There  are  two  sets  of 
cables  leading  from  the  dynamos,  so  that  work  can  be  carried 
out  at  two  different  places  at  the  same  time.  The  cable  from 
one  pole  of  the  dynamo  is  connected  to  some  part  of  the 
boiler,  and  the  cable  from  the  other  pole  is  connected  to  the 
welding  bar  (which  consists  of  a  bar  of  specially  prepared 
steel  about  f$  in.  diameter).  This  welding  bar  is  fixed  in  an 
insulated  holder,  and  on  being  brought  into  contact  with  the 
article  to  be  dealt  with  and  then  withdrawn  a  short  distance, 


WELDING  APPLIED  TO  MAEINE   BOILEKS 


213 


an  electric  arc  is  formed,  which  rapidly  heats  the  parts  in 
close  proximity  to  the  arc,  and  at  the  same  time  the  end  of 
the  bar  is  heated  to  almost  a  molten  condition  ;  this  is  then 


FIG.  112. — Eepairs  to  Lower  Front  Plate  by  Electric  Welding. 

pressed  against  the  parts  to  be  welded,  and  they  being  now 
heated  to  a  welding  temperature,  a  small  portion  of  the  end  of 
the  bar  attaches  itself  to  them,  in  a  similar  manner  as  an 
almost  melted  piece  of  sealing  wax  is  made  to  adhere  to  paper  ; 
after  this  small  portion  of  nearly  melted  metal  is  attached  the 


214 


WELDING  AND  CUTTING  METALS 


bar  is  withdrawn,  thus  breaking  off  the  electric  current.  The 
added  metal  is  then  hammered  to  ensure  its  being  thoroughly 
united  with  the  parts  to  be  welded.  The  welding  bar  is  then 
again  brought  into  contact  with  the  parts  being  dealt  with, 


FIG.  113.— Eepairs  to  the  Bottom  Shell  Plate  by  Electric  Welding. 

and  then  withdrawn  a  short  distance  to  again  form  an  electric 
arc,  and  the  surface  of  the  metal  and  also  the  previously 
welded  metal  are  again  heated  to  a  welding  temperature  and 
another  small  portion  from  the  end  of  the  bar  is  added  and 
hammered  as  before,  and  so  the  cycle  of  operations  continues 
until  sufficient  metal  is  added  for  the  opening  between  the 


WELDING  APPLIED  TO  MAEINE  BOILEES 


215 


two  pieces  of  metal  to  be  entirely  filled  up,  in  the  case  of 
welding  two  plates  together,  or  the  wasted  portions  of  a  plate 
have  been  brought  up  to  the  required  thickness.  The  follow- 
ing are  the  results  of  tests  made  in  June  last  from  a  plate 
welded  by  this  process  (and  as  in  the  case  of  the  oxy-acetylene 
test  samples,  are  the  same  as  those  given  at  the  Institution  of 
Civil  Engineers)  : — 

ELECTRIC  WELDING. 


Breadth. 

Thick- 
ness. 

Area. 

Tons 
Total. 

Tons  per 
Sq.  In. 

Extension  in  4  ins. 
per  cent. 

Ins. 

Ins. 

Ins. 

Not  annealed 

1-0 

•56 

•56 

15-35 

27-4 

12  )  Broke 

Annealed 

i-o 

•55 

•55 

14-5 

26-3 

14  j  through  weld. 

COLD  BENDS. 


Not  annealed 
Annealed 


58° 
160° 


j  Showed  signs  of 
i  fracture  at  weld. 


"It  will  be  seen  that  after  annealing  much  better  results 
were  obtained  than  before  annealing.  But  unfortunately  one 
cannot  anneal  a  boiler  in  place.  Some  cases  of  repairs 
carried  out  by  this  process  can,  I  think,  be  better  explained 
by  showing  sketches  of  them.  Figs.  101,  102  and  103  are,  as 
already  stated,  sketches  of  repairs  carried  out  by  the  oxy- 
acetylene  process,  the  remaining  figures  (104  to  116)  showing 
repairs  carried  out  by  the  electric  welding  process.  Fig.  104 
shows  the  repairs  carried  out  to  the  two  main  boilers  of  a 
well-known  Swedish  vessel.  It  will  be  seen  that  these  are 
double-ended  boilers.  Somewhab  extensive  repairs  were 
carried  out  about  three  years  ago  (the  boilers  are  fifteen  years 
old)  to  the  combustion  chambers  and  furnace  saddle  plates, 
but  they  had  given  trouble  by  leakage,  and  at  the  beginning 
of  this  year  the  landing  edges  of  all  these  patches  and  also 
several  leaky  rivets  and  local  corrosions  were  welded  up  by 


216 


WELDING  AND   CUTTING   METALS 


this  process  ;  some  joints  were,  as  you  see,  welded  up  from 
the  under  side.  I  inspected  these  repairs  after  the  vessel  had 
been  running  about  three  months,  and  found  there  was  not  a 
sign  of  leakage  anywhere.  Fig.  105  shows  a  laminated  tube 
plate  repaired  by  this  process  ;  the  greater  part  of  the  lamina- 


FIG.  114. — Repairs  to  the  Combustion  Chamber  Plating  and  Tube  Plate 
of  Two  Boilers  by  Electric  Welding. 

tion  was  cut  away  and  the  plate  built  up  to  its  required  thick- 
ness as  shown  ;  the  small  screwed  pins  shown  were  put  in  us 
a  safeguard  to  avoid  any  opening  up  of  the  lamination,  in 
case  it  developed  beyond  what  was  thought  to  be  its  extent. 
Fig.  106.  The  landing  edge  of  the  lower  part  of  the  furnace 
and  also  the  combustion  chamber  plating  of  this  boiler  in  way 
of  same  were  wasted  away,  together  with  the  rivet  heads,  and 
these  parts  were  built  up  to  their  original  thicknesses,  the 


WELDING  APPLIED  TO  MAEINE  BOILERS 


217 


rivets  themselves  being  so  fused  to  the  plates  as  to  become 
integral  parts  of  the  same.  Fig.  107.  The  landing  edges  of  a 
leaky  ['patch  in  the  centre  furnace  of  a  small  boiler  were 
welded  to  the  adjoining  plating  as  shown,  also  two  cracks 
in  the  furnace  plating  and  a  wasted  portion  of  the  bottom 
seam  of  the  furnace  was  built  up  to  its  required  thickness 
and  welded  to  the  adjoining  plating.  Fig.  108.  The  plating 


PIG.  115.— Repairs  to  Wasted  Tube  Plate  of  a  Land  Boiler  by  Electric 

Welding. 

of  this  furnace  was  cracked  through  and  wasted  in  way  of  the 
Adamson  rings  and  repaired  as  shown.  Fig.  109.  This  shows 
the  furnace  of  a  small  boiler  which  was  entirely  wasted 
through  in  way  of  the  buttstrap  and  landing  edge  of  the 
furnace  and  combustion  chamber  plating,  and  was  repaired 
as  shown,  the  repairs  taking  three  days.  Fig.  110.  Here, 
again,  repairs  have  been  carried  out  to  a  furnace  in  way  of 
an  Adamson  ring.  Fig.  111.  This  shows  another  repair 
where  the  landing  edge  of  a  furnace  and  combustion  chamber 
plating  and  also  a  wasted  portion  of  a  tube  plate  were 


218 


WELDING  AND   CUTTING  METALS 


repaired.  The  tube  plate  is  not  rightly  shown,  as  it  was  on 
the  water  side  of  the  furnace.  Fig.  112.  This  plate  shows 
the  repairs  carried  out  to  the  wasted  portion  of  the  lower 
front  plate  of  a  marine  boiler ;  it  will  be  seen  that  the  rivets 
were  here  welded  in  to  form  integral  parts  of  the  plate. 
Fig.  113.  This  plate  shows  a  repair  carried  out  to  the  wasted 


Y////////y//A  I  \7/A  i  wft 


FIG.  116.— Repairs  to  the  Wasted  Seam  of  a  Land  Boiler  by  Electric 

Welding. 

landing  edge  of  the  bottom  shell  plate  of  another  main  boiler, 
where  a  length  of  about  5  ft.  was  built  up  to  its  original 
thickness.  Fig.  114.  This  shows  repairs  carried  out  to  the 
combustion  chamber  plating  and  tube  plate  of  two  boilers 
which  were,  as  will  be  seen,  considerably  wasted  and  pitted  by 
corrosion,  in  each  case  the  defective  parts  being  about  3  ft. 
in  length.  Fig.  115.  This  shows  repairs  carried  out  to  a 
wasted  tube  plate  of  a  land  boiler  and  also  to  the  wasted 


WELDING  APPLIED  TO   MAKINE  BOILEES 


219 


landing  edge  of  the  shell  plating.  Fig.  116.  This  shows 
repairs  carried  out  to  the  wasted  seam  of  a  land  boiler.  In 
conclusion,  I  should  like  to  express  my  thanks  to  my  col- 


FIG.  117.— Eepairs  by  Oxy -Acetylene  Process. 

leagues,  Mr.  Bidow,  at  Gothenburg,  and  Mr.  Jones,  at 
Marseilles,  who  have  given  me  the  greater  part  of  the 
information  on  which  this  paper  has  been  written." 

In  its  October  number,   1908,   The  Marine  Engineer  and 


220 


WELDING  AND   CUTTING   METALS 


Naval  Architect  gives  a  description  of  some  interesting 
repairs  carried  out  on  the  boilers  of  the  S.S.  Indraghiri,  in 
the  Victoria  Dock,  London,  during  September.  It  had  been 
found  necessary  to  remove  the  furnaces  from  the  boilers  of 
the  Indraghiri  and  fit  a  new  set,  on  account  of  depressions 
and  other  defects.  In  ordinary  circumstances  the  furnaces 
would  have  required  to  be  cropped  and  ripped  out  by  hand — 
a  long  and  laborious  process — in  order  to  save  disturbing  the 
shell  and  tube  plates.  In  a  very  short  time  the  furnace  tubes 


FIG.  118.— Test  Pieces  from  Oxy- Acetylene  Welded  Plates. 

were  separated  into  pieces  by  the  intense  heat  of  the  oxy- 
acetylene  flame  kept  acting  along  the  line  it  was  desired  to 
rip  them,  the  rivets  cut  out  and  the  divided  furnace  plates 
removed.  In  order  to  adapt  the  fronts  and  back-ends  to 
receive  the  new  furnaces — which  were  of  the  most  modern 
style  with  the  bottle-neck  at  the  fire-box  end — the  front  tube 
plate  was  pieced  and  built  up  to  the  necessary  thickness 
where  defective  by  grooving  action  at  the  top  of  the  furnace 
mouth  and  flanged  to  suit  the  outside  diameter.  The  lower 
part  of  the  fire-box  plating  was  altered  and  flanged  to  suit  the 
flange  of  the  furnace.  The  rest  of  the  work  was  done  in  the 
usual  way  by  the  boiler  makers  employed  by  Messrs.  R.  &  H. 
Green,  Blackwall,  to  whom  the  repairs  were  entrusted.  The 


WELDING  APPLIED  TO  MAEINE   BOILERS  221 

time  taken  to  effect  the  repairs  was  less  than  would  be 
required  by  the  ordinary  course,  and  less  work  was  involved 
in  cutting  away. 

After  the  repairs  were  carried  out  on  the  boilers,  the  usual 
hydraulic  pressure  test  was  applied,  when  the  results  were 
found  satisfactory.  The  steam  pressure  on  the  boilers  is 
200  Ibs. 

The  illustrations  (Figs  117  to  119)  show  the  depressions  in 
the  furnaces,  also  the  work  done  by  the  oxy-acetylene  process, 
and  test  pieces  from  welded  plates. 

The  publication  in  various  parts  of  Dingler's  Polytech- 
nisches  Journal,  1908,  by  Dr.  Hilpert,  of  repairs  on  marine 
boilers  made  by  L.  Chatelier  in  Marseilles,  has  aroused  the 
German  Steam  Boilers'  Associations  to  vigorous  action,  so  far 
as  Germany  is  concerned,  in  the  direction  of  providing  that 
kind  of  safety  which  the  public  has  a  right  to  demand. 

In  the  United  Kingdom,  where  autogenous  welding  is  still 
in  its  infancy,  scarcely  known  even  in  its  most  simple  elements, 
much  less  in  the  serious  and  responsible  application  to  repairs 
on  steam  boilers,  and  more  particularly  marine  boilers,  it  is 
safe  to  assume  that  the  British  Steam  Users'  Associations, 
headed  by  Lloyd's,  will  take  steps  in  a  similar  direction,  so  as 
to  regulate  that  such  repairs  shall  only  be  made  under  the 
most  vigorous  restrictions. 

It  must  not  be  forgotten  that  the  industry  of  compressed 
gases,  more  so  their  application  to  welding,  is  an  entirely  new 
industry,  and  that  the  present  knowledge  is  not  sufficient  to 
advise,  either  as  to  the  mixture  of  the  gases  employed,  the 
best  means  of  keeping  a  proper  mixture,  when  ascertained, 
constant  or  without  decomposition,  more  so  as  it  always  must 
differ  according  to  the  nature  and  thickness  of  the  welding 
metal,  or  as  to  the  right  temperature  of  the  flame. 

Much  less  is  there  evidence,  so  far  as  marine  boilers  are 


WELDING  APPLIED  TO   MAKINE  BOILERS  223 

concerned,  to  show  the  faults  or  defects  of  the  welds  executed. 
It  may  be  easy  to  schedule  the  number  of  repairs  and  the 
names  of  the  steamship  companies ;  but  it  is  difficult,  if  not 
impossible,  to  say  how  many  of  the  accidents  which  so 
repeatedly  occur  are,  more  often  than  not,  caused  by  a  bad 
weld,  which  seemed  to  have  been  properly  executed. 

The  more  the  advantages  of  boiler  repairs  appear,  the 
greater  becomes  the  number  of  those  who,  in  self-confidence, 
are  willing  to  undertake  such  jobs,  as  they  evidently  are  of  a 
lucrative  nature  ;  but  it  is  apt  to  be  forgotten  that  such  repairs 
are  often  required  on  the  most  sensitive  organs  of  the  boiler,  by 
which,  therefore,  certain  conditions  are  required,  and  which 
have  been  duly  defined ;  the  greater  will  also  be  the  responsi- 
bilities of  those  undertaking  to  execute  the  job,  and  perhaps 
more  so  of  those  authorising  the  same  to  be  done,  knowing 
that  there  is  no  means  of  controlling  the  work,  the  only 
guarantee  being  left  to  ocular  inspection  and  to  the  repute  of 
the  welder.  Happily  enough,  the  place  of  the  weld  will  in 
many  instances  offer  difficulties  to  the  unskilled,  securing 
thereby  a  certain  safety. 

Although  welding  with  compressed  gases  has  given  satis- 
factory results,  there  are  many  instances  to  prove  that  the 
industry  is  still  in  its  infancy,  as  even  leading  firms,  which 
are  entitled  to  inspire  confidence,  fail  sometimes  in  producing 
a  satisfactory  weld. 

Far  from  wishing  to  discourage  the  application  of  auto- 
genous welding  to  repairs  on  steam  boilers,  a  disclosure  of  its 
extreme  difficulty,  often  combined  with  great  peril,  will  assist 
in  finding  means  for  overcoming  the  obstacles  and  to  gain 
knowledge  ;  but  until  that  has  been  done  such  repairs  should 
be  entrusted,  under  most  restricted  conditions,  to  persons  only 
who  are  intimately  conversant  with  the  construction  and 
building  of  steam  boilers. 


224  WELDING  AND   CUTTING  METALS 

WELDING  OF  TANKS. 

In  the  majority  of  cases  welding  does  away  with  a  lot  of 
preparatory  work,  caulking  of  edges,  pulling  apart  of  rivets  and 
other  fastenings,  operations  always  expensive,  and  which  are 
always  to  be  avoided  if  possible. 

Take,  for  instance,  the  case  of  a  cylindrical  tank  with  riveted 
bottom  and  head.  If  this  tank  is  not  of  a  sufficient  diameter, 
and  is  not  provided  with  a  manhole,  it  will  be  necessary  to 
make  it  with  at  least  a  convex  bottom  or  head.  Anyway  its 
making  requires  a  riveted  cylindrical  shell  with  two  drawn 
heads  at  the  ends  to  permit  the  riveting  of  bottom  and  head 
and  caulked  edges. 

The  same  tank  can  be  made  by  welding  with  solid  welded 
heads. 

It  may  be  mentioned  that  welding  has  rendered  possible  the 
making,  volume  and  resistance  being  equal,  of  tanks  less 
cumbersome  and  lighter  than  those  before  its  advent,  in  that 
it  has  made  possible  the  building  of  tanks  with  two  convex 
bottoms  without  regard  to  the  diameter  and  absolutely  free 
of  the  double  thickness  of  plates  necessitated  by  riveted 
coverings. 

Nearly  all  the  tanks  built  to  contain  gases  under  pressure 
or  any  liquids,  such  as  petroleum,  are  now  welded,  because, 
apart  from  the  advantages  of  weight,  bulk,  and  price  which 
they  have  over  the  riveted  tanks,  they  do  not  leak,  a  quality 
which  is  difficult  to  obtain  by  riveting,  and  even  with  subse- 
quent tin  soldering,  particularly  when  these  tanks  are  supposed 
to  travel  and  are,  consequently,  subject  to  continual  rough 
handling. 

Besides  the  saving  which  may  be  realised  by  welding  over 
riveting  by  doing  away,  in  a  large  measure,  with  preparatory 
forge  work,  the  economy  of  the  process  in  itself  should  be 
considered. 


WELDING  APPLIED  TO  TANKS 


225 


Take,  for  instance,  the  case  of  the  ordinary  riveting  together 
of  two  plates  of  J-in.  thickness,  as  given  by  The  Boiler  Maker. 

Riveting  (one  line  of  rivets),  diameter  of  rivets  \  in.,  number 
of  rivets  per  foot,  eight. 

Price  paid  to  the  workman  per  foot  of  joint : — 


Laying  out  the  holes 

Marking 

Drilling 

Chamfering 

Eiveting 

Caulking  plates    . 

Caulking  rivets    . 


Total 


0-006 
0-006 
0-029 
0-003 
0-019 
0-004 
0-012 

0-079 


This  cost  does  not  include  the  general  expenses  arising 
from  the  necessary  power,  keeping,  etc.,  of  the  machinery,  and 
heating  of  the  rivets. 

9 

Eight  3-in.  rivets  T23  X  4  cents.    .         .         .     0'04 
Workmanship,  without  general  expenses         .     0*08 


Total  cost  of  riveting,  per  foot 


0*12 


Acetylene     ivelding     (acetylene    generator), 
chamfering  of  edges,  per  foot  .         .         . 


Acetylene  . 
Welding      Oxygen      . 

(  Workmanship 


0'0186 
0'0312 
0'0162 


Total  cost  of  welding,  per  foot 


0*0108 


0*066 


226  WELDING  AND  CUTTING  METALS 

This  shows  conclusively  that  acetylene  welding  is  more 
economical  than  riveting. 

To  complete  the  comparison,  consider  the  case  of  the 
building  of  a  vertical  tubular  trailer  by  acetylene  welding  and 
by  riveting.  Those  operations,  which  are  similar  in  both 
processes  of  manufacture,  are  not  considered  :  shearing  and 
laying  out  of  the  plates,  boring  holes,  assembling  and  expanding 
of  tubes,  etc. 

ACETYLENE  WELDING  (GENERATOR). 

$ 

n,        .    •          \   Shell,  8'5  ft.  X  0-0054  .     '046 

Chamfering 

.     ,  Furnace,  2'925  ft.  X  '0072     .     -021 

oi  edges 

)  Uptake,       5-85  ft.  X  '066      .     '038 

\  Shell,        4-225  ft.  X  '066  .     '278 

Welding  I  Furnace,  1-462  ft.  X  '21  .     '807 

>  Uptake,    2-925  ft.  X  '12  .     -351 

Bounding  and  planing  after  welding        .  .     '60 

Forging  of  furnace  (uptake  and  mouth)  .  .  2*40 

Turning  of  circular  plates        .         .         .  .     '40 

Assembling  of  the  boiler  (mounter  and  help)  .     -80 

Welding,  32'5  ft.  @  $0'27        .         .        |  .  .  8'78 

Total  cost  of  welding         .         .          14*02 

EIVETING. — NECESSARY  PLATE. 

For  shell         .         .         .         .         .         .  Lbs.  5'28 

For  furnace    .         t         .....  4'62 

For  furnace  flanges         .         .                  ,         .  9'90 

For  flanges  of  the  outer  circumferential  plates  51*48 

Total,  71-28  Ibs.  @  $0*25         .         .         .         .  f  1-78 
Forty-four  J-in.  rivets,  5  Ibs. ;  275  f-in.  rivets, 

112  Ibs. ;  117  Ibs.  @  '04      .         .         .         .     4«68 

Brought  forward        ,         f         ,         .  $6'46 


WELDING  APPLIED  TO  TANKS  227 

$ 

Carried  forward         ....  6*46 

Marking  rivet  holes 1*40 

Flanging  the  uptake  with  forge  heat        .         .  1*00 

Closing  in  on  furnace  boiler  head  flanges         .  "80 

Forging  the  furnace  (uptake  and  mouth)          .  4"00 

Closing  in  the  flanges  |  105  Ibs.  X  O'Ol          .  1*05 

of  the  plate    .         .  j  132  Ibs.  X  0'009        .  1-19 

Turning  of  circular  plates        .         .         .  '60 

Assembling  the  boiler 1*60 

5-5  ft.  X  0-08  -44 


Eiveting 

)  35'75  ft.  X  0-117  ....     4-18 

Chipping  and  caulking  heads  ....     T60 
Total  cost  of  riveting          .         $24-32 

The  above  prices  of  riveting  are  taken  on  the  supposition 
that  the  chamfering  and  caulking  are  executed  by  compressed 
air  (except  for  the  heads,  which  require  some  hand  work). 
They  do  not  include  the  general  expenses  (material,  coal,  and 
coke  necessary  for  welding  the  charger,  and  for  the  various 
forge  work). 

These  results  show  the  considerable  saving  obtained  by 
judiciously  using  acetylene  welding  in  boiler-making. 

The  cost  price  may  also  be  made  lower  by  a  preliminary 
heating  of  the  parts  to  be  welded,  using  a  less  expensive  com- 
bustible than  the  acetylene  or  hydrogen  mixture. 

It  is  evident  that  in  every  instance  where  the  method  of 
manufacture,  the  shape  of  the  pieces,  the  place  where  the 
work  is  to  be  done,  will  admit  of  such  a  previous  heating,  a 
great  advantage  will  result  by  bringing  the  parts  to  be  welded 
to  the  highest  practicable  degree  of  heat.  The  more  expensive 
temperature  from  the  blowpipe  is  thus  used  only  for  the  actual 
welding,  which  the  cheaper  way  of  heating  cannot  effect. 

Q  2 


228  WELDING  AND   CUTTING  METALS 

Probably  one  of  the  widest  fields  for  the  adoption  of  the 
autogenous  welding  is  in  keeping  down  the  heap.  There  are 
many  instances,  particularly  in  pressed  steel  work,  where, 
owing  to  the  development  of  a  small  split  or  the  opening  of  a 
seam,  a  large  and  valuable  piece  of  work  has  to  be  scrapped. 
A  few  minutes'  application  of  the  blowpipe  will,  at  an  almost 
insignificant  cost,  in  most  cases  enable  such  a  flaw  to  be 
repaired  and  the  piece  put  into  use. 


CHAPTEE   VII 

CUTTING    METALS 

General — Congress  of  Liege — M.  Jottrand,  La  Societe  1'Oxhydrique — 
MM.  Jottrand  and  Lulli  Process— Installation  for  Cutting  Metals  — 
Speed  of  Cutting — Metropolitan  Railway,  Paris — Hydrogen  Process 
for  Breaking  up  Ships— Cutting  of  Ornamental  Iron — Consumption 
of  Oxygen — Consumption  of  Gas  and  Cost  per  Metre  of  Cutting. 

ONE  of  the  most  important  applications  of  compressed  gases, 
and  more  particularly  that  of  oxygen,  refers  to  cutting  of 
metals. 

The  process  is  the  reverse  to  that  of  welding:  by  welding 
a  reducing  gas  mixture,  by  cutting  an  oxidising  one  by  surplus 
of  oxygen. 

It  is  a  well-known  fact  that  there  are  many  metals  which 
when  brought  to  a  white  heat  burn  in  an  atmosphere  of  pure 
oxygen.  The  experiment  is  familiar  in  every  course  in  physics 
and  chemistry.  The  same  phenomenon  occurs  when  a  jet  of 
oxygen  is,  directed  upon  iron  heated  to  a  bright  red  ;  that  is 
to  say,  the  metal  burns,  and  the  heat  evolved  fuses  the  oxide. 
The  process  for  cutting  metals  by  oxygen  is  based  on  these 
phenomena.  It  can  readily  be  seen  that  it  is  possible  to 
divide  a  piece  of  metal  by  means  of  an  oxygen  jet,  but  it  is 
not  easy  in  practice  to  obtain  a  regular  and  clean  cut. 

At  the  congress  of  Liege,  1901,  M.  Jottrand,  of  La  Societd 
V  Oxhydrique,  exhibited  for  the  first  time  a  blowpipe  for  cutting 
iron  and  steel,  which  created  a  great  deal  of  attention  by 
reason  of  the  important  part  its  development  probably  would 
play  in  metallurgy. 


230  WELDING  AND  CUTTING  METALS 

The  apparatus  consisted  of  an  oxyhydrogen  blowpipe  by 
means  of  which  the  part  of  the  metal  to  be  cut  was  brought 
to  a  bright  red  heat.  Then  the  flow  of  hydrogen  was  cut  off, 
and  the  pure  oxygen  was  increased.  A  good  combustion  was 
produced,  but  it  did  not  proceed  very  long.  The  resultant 
iron  oxide,  not  being  hot  enough,  lacked  fluidity.  It  was 
with  difficulty  removed,  became  mixed  with  the  partially 
melted  iron,  and  thus  obstructed  the  close  contact  of  the 
metal  with  the  oxygen.  The  combustion  stopped,  and  it 
was  necessary  to  bring  the  blowpipe  into  play  again.  The 
manipulation,  even  after  long  practice,  could  produce  only 
an  irregular  cut,  dirty  and  with  edges  incrusted  with  closely 
adhering  oxide. 

The  process  prepared  in  1904  by  Jottrand  and  Lulli  is 
different,  and  remedies  all  the  previously  appearing  difficulties. 
This  process  consists  of  two  blowpipes  in  one  piece,  which 
travel  along  the  section  to  be  cut.  The  first  is  an  ordinary 
oxyhydrogen  blowpipe,  which  heats  the  metal  to  a  bright 
red ;  the  second  one  directs  a  fine  jet  of  pure  oxygen  upon  the 
heated  spot  under  a  pressure  varying  with  the  thickness  of  the 
metal. 

The  action  of  the  two  blowpipes  is  continuous.  The  first 
prepares  the  way  for  the  second,  furnishing  a  volume  of  heat 
sufficient  to  permit  instantaneous  combination  of  the  oxygen 
with  the  metal  in  the  heated  zone.  The  metal  is  not  melted, 
and  the  adjoining  parts  remain  unaltered,  as  the  action  proceeds 
too  rapidly  for  the  heat  to  spread  into  the  mass,  and  the 
oxidised  portion  is  removed  by  the  pressure  of  the  oxygen ; 
the  section  is  cleaner  than  the  raw  cut,  and  its  width  never 
exceeds  4  m.m. 

The  speed  of  travel  of  the  double  blowpipe  is  about  20c.m. 
a  minute ;  in  other  words,  the  operation  is  quite  rapid  and 
comparable  to  hot  sawing.  The  consumption  of  gas  is 


CUTTING  METALS  231 

relatively  small,  depending  upon  the  thickness  of  the  metal  to 
be  cut ;  and  as  the  work  is  rapidly  done,  the  labour  cost  is 
not  important. 

The  double  blowpipe,  which  is  easily  handled,  and  further- 
more may  be  guided  by  any  sort  of  mechanical  device,  is 
available  for  cutting  not  only  thick  plates,  but  also,  and  with 
equal  ease,  tubes,  beams,  shafts,  and  all  sorts  of  rolled 
sections. 

The  cutting  may  be  made  to  follow  any  line,  executing  all 
sorts  of  curves  and  profiles,  the  smoothness  of  the  surface 
depending  a  great  deal  upon  the  skilful  handling  of  the 
blowpipe.  The  reaction  takes  place  almost  immediately ; 
therefore  even  a  shaking  of  the  hand  or  raising  or  lowering 
of  the  blowpipe  will  cause  an  uneven  surface.  In  all  cases 
where  a  special  appearance  is  desirable — for  instance,  the 
cutting  of  manholes,  locomotive  frames — it  is  advisable  to  use 
a  mechanical  appliance  to  guide  the  blowpipe. 

An  installation  for  cutting  of  metals  is  extremely  simple, 
and  consists  of  : — 

1.  The  cutting  blowpipe  with  various  exchangeable  burners 
to  suit  the  different  thicknesses  of  metal. 

2.  A  high  pressure  regulator  up  to  thirty  atmospheres. 

3.  A  high  pressure  rubber  tube. 

Besides  the  hydrogen-cutting  blowpipe  before  mentioned, 
there  are  various  other  constructions,  especially  for  the  use  of 
acetylene  instead  of  hydrogen.  One  may  be  equally  as  good 
as  the  other  known  under  various  names,  but  this  is  of  little 
importance,  as  the  blowpipes  are  generally  obtainable  on  trial, 
so  as  to  enable  the  choice  of  the  best  construction  for  the 
special  work  in  view. 

As  the  pressure  of  the  gases  in  the  receptacles,  the  ordinary 
steel  cylinders,  is  high,  being  about  150  atmospheres  when 
filled,  the  gas  passes  through  a  pressure-reducing  valve  before 


232  WELDING  AND   CUTTING  METALS 

being  used.  The  pressure  of  the  oxygen,  when  used  for 
cutting,  varies  from  about  one  and  a  half  to  five  atmospheres, 
for  the  hydrogen  or  any  other  combustible  gas  used  a 
water  pressure  of  20  c.m.  being  sufficient. 

The  process  of  cutting  metals  is  in  no  way  limited  by 
the  mechanical  properties  of  the  material,  whether  it  be  hard  or 
soft,  tempered  or  annealed,  chrome  or  nickel,  the  steel  burning 
just  as  fast. 

The  problem  of  cutting  armour  plates  is  thus  fully  solved. 

It  might  be  assumed  that  the  metal  would  be  severely 
attacked  on  the  surface  by  the  influence  of  the  oxygen,  but 
this,  however,  is  claimed  not  to  be  the  case.  With  the  exception 
of  a  layer  of  O'Ol  in.,  at  the  most,  next  to  the  cutting  edge, 
the  metal  keeps  its  original  chemical  composition,  and  the 
physical  properties  remain  the  same. 

The  essential  qualities  of  the  process  may  be  thus  sum- 
marised :  extreme  simplicity  of  the  installation  and  appliances ; 
complete  mobility  ;  independence  of  any  need  of  motive  power; 
absence  of  any  reaction  upon  the  tool ;  extraordinary  speed  of 
operation  ;  and,  so  to  speak,  unlimited  adaptability. 

In  illustration  of  the  rapidity  which  above  all  charac- 
terises the  oxyhydrogen  cutting,  J.  B.  van  Brussel  gives 
some  interesting  examples  in  a  paper  recently  read  by  him, 
abstracts  of  which  appear  in  the  Engineering  Magazine,  as 
follows  : — 

An  armour  plate  160  m.m.  (6'3  ins.)  thick  was  cut  to  a 
length  of  1  metre  in  ten  minutes.  A  cut  of  similar  length 
in  a  plate  15  m.m.  thick  took  less  than  five  minutes,  and  the 
cost  of  application  did  not  exceed  1*50  franc. 

To  cut  a  manhole  BOO  by  400  m.m.  (12  by  16  ins.)  in  a 
plate  20  to  30  m.m.  (0*8  to  1*2  in.)  thick  requires  four  to  five 
minutes. 

An  opening  150  by  150  m.m.  (6  by  6  ins.)  in  a  tube  5  m.m. 


CUTTING  METALS  233 

thick  required  three  to  four  minutes,  while  the  cutting  of 
the  same  opening  with  ordinary  tools  would  need  from  three 
to  forty  minutes,  the  cost  of  this  work  being  about  fifteen 
centimes. 

Another  very  striking  example  was  furnished  at  the  station 
of  the  Metropolitan  Railway  at  Place  d'ltalie,  in  Paris.  It 
was  necessary  to  cut  away  an  iron  staircase,  6  metres  high, 
the  width  of  which  impeded  the  traffic.  It  was  cut  down  to  a 
width  of  1  metre  in  four  hours'  time. 

At  Bremen,  Germany,  the  hydrogen-cutting  process  has 
been  used  for  breaking  up  ships,  and  among  other  records  the 
following  time  data  are  interesting  : — 

A  plate  300  m.m.  (12  ins.)  thick  was  cut  for  a  length  of 
1  metre  to  a  depth  of  426  c.m.  in  seven  minutes.  The  same 
plate  had  been  cut  with  a,  pneumatic  chisel  along  the 
length  of  1*15  metre  and  to  a  depth  of  1*5  c.m.,  but  this 
work  had  required  one  hour. 

The  hydrogen  method  was  also  used  for  rivet  cutting ;  in 
less  than  twelve  seconds  the  head  of  a  22-m.m.  rivet  could 
be  burned  without  any  injury  to  the  plate ;  the  rivet  was 
then  driven  out  with  a  punch. 

The  maximum  thickness  which  has  yet  been  cut  is  210  m.m. 
(8*27  ins.)  in  armour  plates,  but  300  m.m.  has  been  reached 
in  round  shafting. 

As  a  matter  of  curiosity  some  work  done  by  the  aid  of  the 
hydrogen  jet  by  the  Deutsche  Oxyhydric  Company  m&y  be  men- 
tioned. A  large  bunch  of  grapes  with  leaves  and  branch  of 
the  vine  was  cut  out  from  ordinary  thin  sheet  iron.  The 
imitation  was  good,  and  although  the  piece  was  of  iron,  it  was 
very  light.  A  branch  of  a  pear  tree  with  a  large  nice-looking 
pear  and  two  leaves,  and  also  a  "  lily  of  the  valley "  were 
made  in  the  same  way. 

The  following  table  gives  the  consumption  of  oxygen  by 


234 


WELDING  AND   CUTTING  METALS 


the  Fouche  blowpipe,  and  the  time  required  for  cutting  up 
metals  of  various  thicknesses  : — 


Thickness  of  Metal. 
Millimetres. 

Consumption  of 
Oxygen. 
Litres. 

Time  of  Cutting. 

Minutes. 

Seconds. 

5 

110 

2 

50 

10 

140 

4 

— 

15 

230 

4 

30 

20 

270 

5 

45 

30 

370 

6 

— 

40 

420 

6 

— 

50 

550 

6 

30 

75 

900 

7 

— 

100 

1500 

8 

— 

150 

2200 

10 

— 

The  Chemische  Fabrik  Griesheim-Elektron  gives  consumption 
of  gas  and  cost  per  metre  of  cut  length  as  follows  :— 


Thickness 
of  Metal. 
Millimetres. 

Time  of 
Cutting. 
Minutes. 

Consumption  of  Gas  in 
litres. 

Cost  of  Gas  in  pfennige  at 
hydrogen,  1  mark  per  c.b.m., 
oxygen,  1  mark  per  c.b.m. 

Hydrogen. 

Oxygen. 

Hydrogen. 

Oxygen. 

Total. 

Blowpipes  for  2  to  50  m.m.  thickness 


2 

5—6 

40 

45  . 

4-0 

13-5 

17-5 

3 

5—6 

55 

55 

5-5 

16-5 

22-0 

4 

5—6 

65 

70 

6-5 

21-0 

27-5 

5 

5—6 

70 

80 

7-0 

24-0 

31-0 

6 

5—6 

80 

95 

8-0 

28-5 

36-5 

8 

5—6 

95 

115 

9-5 

34-5 

44-0 

10 

5—6 

100 

140 

10-0 

42-0 

52-0 

12 

6—7 

105 

165 

10-5 

49-5 

60-0 

15 

6—7 

110 

200 

11-0 

60-0 

71-0 

20 

6—7 

110 

260 

11-0 

78-0 

89-0 

25 

6—7 

115 

325 

11-5 

97-5 

109-0 

30 

6—7 

115 

390 

11-5 

117-0 

1285 

35 

6—7 

120 

450 

12-0 

135-0 

147-0 

40 

6—7 

120 

510 

12-0 

153-0 

165-0 

45 

6—7 

125 

580 

12-5 

174-0 

186-5 

50 

6—7 

125 

650 

12-5 

195-0 

207-5 

CUTTING  METALS 


235 


Thickness 
of  Metal. 
Millimetres. 

Time  of 
Cutting. 
Minutes. 

Consumption  of  Gas  in 
litres. 

Cost  of  Gas  in  pfennige  at 
hydrogen,  1  mark  per  c.b.m., 
oxygen,  3  marks  per  c.h.m. 

Hydrogen. 

Oxygen. 

Hydrogen. 

Oxygen. 

Total. 

Blowpipes  for  50  to  250  m.m.  thickness. 


50 

7—8 

240 

600 

24 

180 

204 

55 

7—8 

250 

675 

25 

203 

223 

60 

7—8 

260 

740 

26 

222 

248 

65 

7—8 

275 

820 

28 

276 

274 

70 

7—8 

290 

880 

29 

264 

293 

75 

7—8 

300 

970 

30 

291 

321 

80 

8—9 

310 

1050 

31 

315 

376 

90 

8—9 

320 

1200 

32 

360 

392 

100 

8—9 

325 

1400 

33 

420 

453 

125 

8—9 

350 

1850 

35 

555 

590 

150 

8—9 

380 

2330 

38 

705 

743 

175 

10—12 

400 

2850 

40 

855 

895 

200 

10—12 

425 

3350 

43 

1005 

1078 

225 

10—12 

460 

3860 

46 

1158 

1204 

250 

10—12 

500 

4500 

50 

1350 

1700 

CHAPTEE  VIII 

REPORTS  UPON  ACETYLENE  WELDING 

Dr.  Hilpert — Griesheim-Elektron — Dr.  Michaelis — Belgian  Steam  Users' 
Association — French  Steam  Users'  Association  (Veritas) — German 
Steam  Users'  Association — Manchester  Steam  Users'  Association — 
International  Steam  Users'  Association. 

Dr.  A.  Hilpert,  Ingenieur,  Professor  at  the  High  Technical 
College,  Charlottenburg,  Berlin,  in  part  24,  1908,  of  Dingier 's 
Polytechnisches  Journal,  reports  as  follows  : — 

"  In  respect  of  the  application  of  acetylene  welding  to 
repairs  on  steam  boilers,  and  more  particularly  those  of  the 
marine  type,  my  tests  and  examinations  during  a  period  of 
more  than  one  and  a-half  years  entitles  me  to  the  opinion  that 
the  present  means  offered  by  the  autogenous  welding  in 
Germany  are  not  sufficiently  advanced  for  the  application 
to  repairs  on  steam  boilers. 

"  My  said  experiments  were  not  carried  out  with  a  view  to 
test  repairs  made  on  steam  boilers  by  the  aid  of  acetylene 
welding — as  at  that  time  this  system  was  almost  unknown — 
but  for  purpose  of  ascertaining  to  what  extent  acetylene 
welding  could  be  applicable  to  various  materials  of  different 
thicknesses. 

"  For  cast-iron,  tempered  iron  or  steel,  and  nickel-steel,  I 
have  obtained  no  satisfactory  results ;  better  results  were 
obtained  for  cast-steel,  mild  ingot-steel,  and  particularly 
for  pig-iron. 

"  In  my  opinion,  the  greatest  field  of  operation  will  be  found 
for  acetylene  in  its  application  to  welding  of  pig-iron. 


KEPORTS  UPON  ACETYLENE  WELDING 


237 


"  The  pig-iron  material  used  for  the  experiments  had  a 
tensile  strength  of  37—39  kg.  g.m.m.  and  an  elongation 
Of  28 — 31  per  cent.,  on  a  length  of  200  m.m.  The  experi- 
ments were  carried  out  upon  plates  of  4 — 20  m.m.  thickness 


v.H. 


IIU 

100 
90 
SO* 
70 
50 
50 
40 
30 
20 
10 

or 

^< 

^.^ 

"\ 

•«xs>(^! 

1 

i        ( 

>-**> 

. 

"^ 

\^j 

N 

<v     ' 

: 

^\ 

\ 

1 

L 

\ 

\  ' 

i 

i 

^ 

c 

>         ^ 

54         5         6         /O        /2             /5                      20 

FIG.  120.— Influence  of  different  Thicknesses  of  Material  upon  the  Strength 
and  Ductility  of  Autogenous  Acetylene  Welds.  Swedish  Welding- 
rod  was  used  and  the  Welds  were  hammered. 

by  means  of  Fouche's  blowpipes  and  acetylene  generated  in 
an  apparatus  of  the  best  construction  and  of  a  sufficient  size 
for  producing  the  quantity  of  gas  required. 

"  So  far  as  strength  is  concerned,  satisfactory  results  were 
obtained,  but  it  was  found  that  the  strength  decreases  with 
increased  thickness  of  the  plate.  The  strength  of  plate-weld 


238 


WELDING  AND   CUTTING  METALS 


on  20  m.m.  thickness  was  found  to  be  in  average  70  per 
cent,  of  the  strength  of  the  material.  More  unfavourable 
were  the  results  in  regard  to  stretching,  being  satisfactory 
for  thin  plates,  but  sinking  rapidly  for  plates  of  greater  thick- 


4000 


3000 


2000 


—  Hammered  Weld. 
Kg./q.c.m. 


O  =  Unhammered  Weld. 


1000 


15 


20  mm. 


FIG.  121. — Influence  of  Mechanical  Treatment  of  Autogenous  Acetylene 
Welds  on  Plates  of  Various  Thicknesses. 

nesses.  It  was  found  in  the  latter  case  that  the  weld  itself  was 
less  affected  by  the  stretching.  The  bending  tests  over  a 
roller  of  80  m.m.  diameter  gave  for  small  thicknesses  satis- 
factory results,  but  those  of  12  m.m.  were  uncertain. 

"  In  all  the  tests,  the  best  results  were  obtained  in  which 
the  welding-rod  was  almost  carbon  free  and  in  which  the 
weld  was  completed  by  hammering  and  annealing. 


EEPOETS  UPON  ACETYLENE  WELDING 


239 


"  Fig.  120  shows  the  influence  of  increased  thickness  of  plates 
from  4  to  20  m.m.  upon  the  strength  and  ductility  of  auto- 
genous welds,  expressed  in  percentage  of  those  of  the  unwelded 


v.  H. 


110 
100 

90 
80 
70 
60 
50 
40 
30 
20 
10 


10        12 


15 


20  mm. 


FIG.  122. — Influence  of  Welding-rods  of  Different  Qualities  upon  the 
Strength  and  Ductility  of  Autogenous  Acetylene  Welds  on  Plates 
of  Various  Thicknesses. 


a  =  Welding-rod  of  Soft  Iron,  the  Weld 

hammered. 
b  =  Welding-rod    of    Swedish    Iron,    the 

Weld  hammered, 
c  =  Do.,  do.,  but  the  Weld  unhammered. 


d  =  Welding-rod  of  Siemens-Marten  Steel 

Weld  hammered. 
—  =  Strength. 
— .—  =  Ductility. 


material.       Swedish  welding-rod  was  used  and  the  welds  were 
hammered. 

"Fig.  121  gives  the  tensile  strength  of  the  seam  of  auto- 
genous-welded soft-iron,  and  also  the  influence  of  mechanically 
finishing  the  weld. 


240  WELDING  AND   CUTTING  METALS 

"  Fig.  122  gives  in  similar  way  as  Fig.  120,  the  difference, 
expressed  in  percentage,  obtained  by  the  use  of  three  different 
welding-rods,  that  marked  with  the  letter  I  (about  0*05°  C.) 
giving  the  best  result. 

"  I  may  also  state  the  reasons  why  I  have  not  used  my  said 
results  as  a  criticism  upon  the  repairs  carried  out  by  the 
acetylene  welding  in  Marseilles.  Firstly,  the  circumstances 
differ  in  this  respect,  that  the  welding  seam  produced  on  the 
steam  boilers  working  under  heavy  strain  cannot  be  compared 
with  a  seam  made  on  a  test  bar  in  a  laboratory ;  secondly,  the 
acetylene  used  by  me  and  generated  in  a  separate  generator 
cannot  be  compared  with  acetylene  used  in  Marseilles,  as  being 
comparatively  pure  and  delivered  compressed  in  cylinders. 

"  It  is  hoped  that  even  in  Germany  during  the  next  few 
years,  particularly  in  the  large  sheet-iron  works,  where 
acetylene  welding  has  been  used,  better  results  than  mine 
may  be  produced,  based  upon  practical  knowledge  and 
experience. 

"  It  remains  a  fact,  however,  that  repairs  of  a  most  difficult 
nature  have  been  made  on  steam  boilers,  without  any  objection- 
able remarks,  and  so  far  as  I  can  judge,  the  excellent  results 
obtained  may  be  entirely  attributed  to  the  properly  instructed 
and  particularly  skilful  staff  of  workmen ;  to  the  use  of  very 
pure  acetylene  and  to  the  mechanical  treatment  of  the  weld." 
Dr.  L.  Michaelis  (Autogen  Werke,  Berlin),  in  No.  8,  1908,  of 
Die  Zeitschrift  des  Bayerischen  Revisions   Vereins,  gives  his 
opinion  as  to  the  conditions  required  in  order  to  produce  a 
satisfactory  acetylene  weld  as  follows  :— 
"  1.  The  use  of  chemically  pure  acetylene. 
"  Such  a  gas  has  not  been  obtainable  in  Germany,  there 
being  no  works  for  the  production  of  acetylene-dissous.     This 
gas  is  by  a  special  method  compressed  in  steel  cylinders,  in 
similar  way  as  compressed  hydrogen  and  oxygen.     It  possesses 


EEPORTS  UPON  ACETYLENE  WELDING  241 

all  the  virtues  of  hydrogen  in  respect  of  purity  of  gas  and 
portability  of  the  apparatus,  combined  with  the  economy  and 
extension  of  acetylene  welding.  Acetylene  could  therefore,  up 
to  recently,  be  obtained  in  Germany  from  special  generators 
only,  which  generally  were  too  small  or  generated  the  gas  too 
quickly,  producing  thereby  a  gas  of  unsatisfactory  purity. 

"  The  repairs  on  steam  boilers  must  generally  be  done  in  a 
small  space.  The  welder  requires  the  welding  apparatus  as 
near  as  possible,  and  as  the  space  available  prevents  the  fixing 
of  a  cumbrous  apparatus,  it  remains  only  to  use  one  as  small 
as  possible,  which  will,  however,  by  reason  of  the  great  strain 
it  will  be  exposed  to,  deliver  bad  gas.  The  first  condition  for 
repairs  on  steam  boilers  is  therefore  to  abandon  the  genera- 
tors, as  they  cannot  under  the  circumstances  produce  the 
quality  of  the  gas  as  required.  When,  on  the  other  hand, 
acetylene-dissous  is  obtainable,  then  a  pure  and  cold  gas  can 
be  used  at  any  place. 

"  2.  Another  not  less  important  point  is  the  blowpipe.  It  can 
be  proved  in  most  instances  that  the  blowpipes  obtainable  at 
the  lowest  price  are  those  generally  used.  The  conditions  as 
to  quality  have  not  yet  been  extended  to  blowpipes. 

"  A  satisfactory  blowpipe  should  fulfil  the  following 
conditions  :— 

11  (a)  The  gases  must  remain  mixed  in  proper  proportions. 

"  (b)  The  gases  must  leave  the  burner  with  a  certain  velocity, 
so  as  to  keep  the  metal  fluid,  without  chasing  the  metal. 

"  (c)  The  flame  must,  in  certain  welding  operations,  have  a 
pressure  sufficient  to  prevent  the  melted  metal  to  drip  from 
the  weld.  All  burners  working  with  oxygen  under  pressure 
and  acetylene  without  pressure  become  after  a  short  time  of 
working  useless.  The  radiating  heat  affects  the  oxygen,  which 
is  under  pressure,  with  great  velocity  in  a  narrow  space,  in  a 
different  way  than  its  action  upon  the  acetylene  contained  in 

w.  R 


242  WELDING  AND  CUTTING  METALS 

a  larger  space  and  without  pressure.  The  result  is  a  decom- 
position of  the  flame  and  a  burning  of  the  metal.  This  can 
only  be  prevented  by  a  skilful  welder.  It  is  therefore  a 
difficult  task  to  produce  a  burner  in  which  the  gases  are  kept 
under  pressure  in  such  a  way  so  as  to  offer  the  same  results  in 
respect  of  expansion. 

"3.  If  the  technical  conditions  have  been  fulfilled  and  the 
acetylene-dissous  is  to  be  manufactured  in  Germany,  the 
remaining  condition  of  supplying  a  sufficiently  trained  staff 
offers  very  great  difficulties.  Le  Cliatelier,  Marseilles,  for 
instance,  does  not  permit  any  of  his  mechanics  to  even 
attempt  to  make  a  weld  unless  he  has  had  at  least  six 
months'  training  at  the  works. 

"  I  wish  to  contradict  the  statement  made  that  it  would  be 
impossible  to  make  a  perpendicular  weld  or  one  in  a  roof,  as 
not  only  could  such  a  defect  be  repaired  by  welding,  but  the 
mechanic  could  even  remain  resting  on  his  back  repairing 
any  defects  above  him.  The  welding  under  such  circum- 
stances must  of  course  be  made  by  means  of  suitable 
burners,  so  as  to  prevent  the  melted  metal  from  the  welding 
rod  to  drip.  It  is  often  necessary  to  have  the  welder  trained 
for  weeks  in  the  dark  to  enable  him  to  judge  the  flame,  and 
to  prevent  its  decomposition,  as  repairs  on  steam  boilers  are 
generally  made  in  the  dark  and  not  in  a  well-lighted  workshop. 
The  welder  should  also  be  prevented  from  long  continuous 
working,  as  the  faintest  shake  of  the  blowpipe  may  often 
result  in  an  unsatisfactory  weld ;  he  must,  of  course,  be  paid 
accordingly.  The  firm  undertaking  repairs  on  steam  boilers 
must  be  provided  with  a  skilled  staff  of  workmen,  in  interest 
of  public  safety. 

"  4.  Another  important  point  in  the  production  of  a  satisfac- 
tory weld  is  the  composition  of  the  welding  rod  from  the  metal 
of  which  the  crack  or  defect  is  to  be  filled.  Based  upon  my 


EEPOETS  UPON  ACETYLENE  WELDING  243 

own  experience  and  upon  the  results  obtained,  the  size  of  the 
welding-rod  plays  also  an  important  part. 

"  5.  The  last,  but  not  the  least,  important  part  is  the  com- 
pletion of  the  weld  by  mechanical  means,  such  as  hammering 
or  otherwise.  The  technical  and  ingeniously  arranged 
mechanical  appliances  in  this  respect,  as  used  by  Le  Chatelier 
and  others,  and  being  the  sine  qua  non  of  a  satisfactory 
weld,  are  naturally  withheld  from  inspection  by  competitors. 
It  may,  however,  be  stated  that  the  said  means  consist  of 
hammering  and  annealing,  means  which  are  also  being  used 
in  welding  by  water-gas.  So  far  as  annealing  is  concerned,  my 
own  examinations  tend  to  show  that  it  has  no  influence  upon 
the  strength  and  elasticity,  but  produces  a  more  homogeneous 
weld. 

"  How  far  these  conditions  may  assist  in  the  production  of  a 
satisfactory  weld,  experience  and  tests  alone  can  show.  There 
is  reason  to  believe  that  such  tests  will  be  carried  out  in 
Germany  within  a  reasonable  time  and  on  a  large  scale  by 
proper  authorities,  not  merely  on  test  rods  in  the  laboratory 
but  upon  actually  welded  articles.  The  importance  of  such 
tests  cannot  be  over-estimated." 

The  Chemische  Fabrik  Griesheim-Elektron,  carrying  on 
hydrogen  welding  on  a  large  scale,  in  a  recent  letter  addressed 
to  the  Bayerischen  Revisions  Verein,  say  : — 

"  Eepairs  on  steam  boilers  by  means  of  autogenous  welding 
should  be  prohibited,  because  a  perfect  weld  can  only  be  pro- 
duced on  a  horizontal  and  easily  accessible  surface.  Corrosion 
on  a  perpendicular  surface  cannot,  in  general,  be  welded  satis- 
factorily ;  besides,  the  plates  are  generally  of  a  thickness  of 
more  than  10  m.m.,  and  by  such  thickness  an  unsatisfactory 
weld  only  can  be  the  result,  even  with  the  acetylene  flame, 
which  produces  a  flame  of  considerable  heat.  It  is  evident 
that  by  means  of  this  kind  of  welding,  a  perpendicular  or 

B  2 


244  WELDING  AND  CUTTING  METALS 

overhanging  weld  cannot  be  done.  Independent  of  the  unsatis- 
factory repairs  of  steam  boilers  by  means  of  welding,  very  few 
suitable  opportunities  would  be  offered." 

C.  L.  J.  Hartmann,  an  authority  in  Hamburg,  in  a  letter 
dated  22nd  April,  1908,  says :  "  Electric  welding  has  for  years 
been  used  here  for  repairs  on  marine  boilers  with  great 
advantage.  It  must,  however,  be  stated  that  the  respective 
firms  using  the  system  are  fully  conversant  with  boiler 
making.  Experience  has  also  here  proved  that  attempted 
repairs  of  tension  cracks  have  been  unsatisfactory. 

"  I  take  as  great  an  interest  in  autogenous  welding  as  in 
any  industrial  development,  and  I  truly  hope  that  it  will, 
besides  the  electric  welding,  bring  advantages  to  the  ship- 
building, but  without  injury  to  public  safety.  Precaution  is, 
however,  advisable,  and  it  is  necessary  to  be  careful  not  to 
embark  upon  an  insecure  territory,  otherwise  the  reaction 
will  not  fail,  and  the  autogenous  welding  will  disappear  as 
quickly  as  it  came." 

The  Bayerischen  Revisions  Verein  (the  Bavarian  Steam 
Users'  Association),  in  its  technical  reports  for  1907,  states: — 

"  Taken  all  in  all,  there  are  in  Germany  for  the  present  a 
few  firms  only  which  offer  guaranty  enough  for  the  safety  of 
welding  applied  to  repairs  on  steam  boilers  and  steam  vessels, 
and  these  firms  seem  especially  to  carry  out  repairs  on  marine 
boilers. 

"  Unfortunately,  the  number  of  persons,  without  necessary 
knowledge  and  experience,  or  suitable  appliances,  and  more 
particularly  without  the  properly  trained  staff  of  workmen, 
which  offer  to  carry  out  the  difficult  repairs  on  steam  boilers 
is  very  great  indeed,  and  their  great  anxiety  to  obtain  such 
jobs  stands  in  reverse  proportion  to  their  ability. 

"In  our  opinion,  the  autogenous  welder  must,  in  his  pro- 
fession as  such,  stand  authoritatively  independent  and  he  must 


EEPORTS  UPON  ACETYLENE  WELDING  245 

also  be  a  boiler  maker,  otherwise  his  care  for  our  steam 
boilers  would  offer  a  danger  which  cannot  be  over-estimated. 
This  is  applicable  to  all  times,  even  if  the  best  results  should 
be  obtained  by  a  skilful  application  of  autogenous  welding 
to  steam  boilers. 

"  We  must  therefore  advise  our  members,  at  least  for  the 
present,  to  refrain  from  the  adoption  of  new  methods,  and 
rather  retain  the  old  and  safe  methods ;  and,  besides,  not  to 
permit  any  welding  to  be  done  in  cases  where  extension  and 
bending  are  points  of  importance,  or,  at  least,  to  entrust 
the  welding  to  such  firms  only  which  possess  not  only  great 
experience  in  such  work  but  also  are  boiler  makers. 

"But  the  advice  to  adopt  the  position  of  waiting  until 
experience  and  tests  have  given  satisfactory  results  must  not 
be  taken  as  a  condemnation  of  autogenous  welding.  On  the 
contrary,  the  indisputable  great  advantages  offered  by  this 
system  can  only  be  in  the  interest  of  industry  as  soon  as 
satisfactory  tests  will  admit  its  adaptability,  especially  to  repairs 
on  steam  boilers." 

The  Bayerischen  Revisions-Verein  (the Bavarian  Steam-Users' 
Association)  has  recently  sent  to  the  inspectors  of  their  Steam 
Boilers  Control  Associations  the  following  circular,  which  reads, 
in  translation,  as  follows  :— 

"  1.  The  owners  of  steam  boilers  are  advised  to  discourage 
the  application  of  welding  on  repairs  of  such  surfaces  which 
are  exposed,  during  work,  to  stretching  and  bending;  and 
also 

"  2.  To  refrain  from  engaging  for  welding  repairs  any  firm 
which  by  their  installations  or  knowledge  does  not  give  guaranty 
as  to  being  able  to  carry  out  such  tasks,  which  are  often  of  a  very 
difficult  nature,  and  for  such  purpose  to  consider  only  such 
firms  which  are  known  to  be  professionally  and  thoroughly 
conversant  with  repairs  in  steam  boilers. 


246  WELDING  AND   CUTTING  METALS 

"  3.  When  the  repair  by  welding  is  not  limited  to  small 
spaces  or  grate-bars,  a  district  water  pressure  test  must  always 
be  made  in  accordance  with  the  stipulations  in  reference  to 
such  pressure  tests,  and  the  weld  should  be  hammered  during 
such  test  being  made. 

"  The  same  is  applicable  to  approbation  tests  and  wholly  or 
partly  new  steam  boilers  or  vessels  which  have  been  finished 
by  welding.  The  weld  must  always  be  inspected  before  and 
after  the  pressure  test,  even  on  the  water  side. 

"4.  On  this  occasion  it  is  also  advisable  to  arrange  so  that  the 
weld  may  be  made  accessible  for  inspection,  even  during  the  work. 

"5.  In  the  event  of  an  inspection  during  the  working  being 
impossible,  the  boiler  must  then,  within  three  months,  or  in 
the  other  case,  within  six  months  at  the  most  from  the  date  of 
repair,  be  subjected  to  an  interior  inspection,  when  the  weld 
must  be  thoroughly  inspected  on  the  water  as  well  as  on  the 
inner  surface ;  the  interior  test  must,  if  necessary,  be  done  by 
water  pressure. 

"  If  the  weld  is  thus  found  to  be  perfect,  further  interior 
inspection  of  Associations'  boilers  is  postponed  for  one  year 
(instead  of  two  years). 

"  Applications  for  alterations  of  the  time  of  inspection  may  be 
filed  and  addressed  to  the  respective  officers  of  the  Official 
Control  of  Boilers,  and  reports  of  all  such  inspections  and 
pressure  tests  must  be  filed  with  the  Board. 

"  6.  All  the  inspection  members  must  make  inquiries  in  every 
case  as  to  which  firms  carry  out  welding  repairs  on  steam 
boilers  and  steam  vessels,  where  and  on  which  boiler,  etc., 
such  repair  has  been  done.  Such  boilers  must  as  soon  as 
possible  be  scheduled  and  inquiries  made  as  to  the  reason  of 
and  in  what  way  such  repairs  were  made,  and,  if  possible,  an 
inspection  of  the  weld  should  be  made  at  the  same  time, 
eventually  by  the  water-pressure  test." 


EEPOETS  UPON  ACETYLENE  WELDING  247 

Dr.  Hilpert,  in  No.  10,  dated  31st  May,  1908,  of  the  Zeits- 
chrift  des  Bayerischen  Revisions  Vereins,  page  107,  publishes 
copies  of  the  following  three  letters  :— 

1.  Compagnie  des  Messageries  Maritimes,  No.  169. 

"  In  reply  to  your  letter  of  31st  October,  N.  408,  A.  D.  14, 
I  am  glad  to  inform  you  that  the  numerous  repairs  on  several 
of  our  boilers  carried  out  by  you  by  means  of  your  welding 
system  have  given  me  full  satisfaction. 

"  Welding  has  been  done  on  cracks,  and  pieces  have  been 
welded  to  tube-walls  in  order  to  fill  out  flange  joints  which 
had  been  damaged  by  corrosion. 

"  None  of  these  repairs  has  up  to  now  given  any  reason  of 
complaint. 

"  Yours, 

"  La  Aotat,  "  The  Director  of  Works, 

"  5  November,  1907."  (Signed)     "  RAYMOND." 

2.   General  Direction,  "  Veritas,"  Paris. 

"  The  undersigned,  Jacques  Elie  Boissevain,  inspector  of 
*  Veritas  '  Bureau  in  Marseilles,  certifies  hereby,  by  order  of 
the  general  direction  of  '  Veritas,'  in  accordance  with  letter 
of  7th  August,  1907,  that  the  numerous  repairs  on  ships  or 
ship  boilers,  which  have  been  carried  out  by  the  Societe  de 
VAcetylene-Dissous  de  Sud-Est  in  Marseilles,  under  the  super- 
vision of  our  engineers  at  our  Marseilles  Bureau  '  Veritas,' 
have  given  us  full  satisfaction,  and  that,  accordingly,  the 
Board  has  authorised  the  said  company  to  carry  out  such 
repairs  on  all  ships  controlled  by  '  Veritas '  in  any  country. 

"  The  Inspector  of  the  Veritas  Bureau 
"  Marseilles,  in  Marseilles, 

"  9th  August,  1907.  "  (Signed)     "BOISSEVAIN." 


248  WELDING  AND   CUTTING  METALS 

3.  Belgian  Steam   Users'  Association. 

"  Hereby  I  inform  you  that  my  firm  has  been  authorised  to 
use  the  following  words  added  to  the  heading  of  our  notepaper  : 

"  '  Travaux  executes  avec  1'autorisation  et  sans  la  surveillance 
de  1'association  pour  la  surveillance  des  chaudieres  a 
vapeur.' 

"  Antwerp,  (Signed)     "  CHAMPY  FRERES." 

"  28th  April,  1908." 

The  Manchester  Steam.  Users'  Association,  in  a  letter  of 
24th  August,  1908,  addressed  to  the  Author,  their  Chief 
Engineer,  Mr.  C.  E.  Stromeyer,  says  : — 

"  I  have  absolutely  no  experience  as  regards  modern  welding 
practices  in  boilers.  The  old  methods  are  barbarous,  and  are 
sanctioned  only  for  plates  which  are  in  compression,  and  I 
should  be  delighted  if  welds  could  now  be  made  reliable  enough 
for  parts  subjected  to  tension  or  bending,  but  you  must  not 
forget  that  the  personal  element  enters  into  the  question,  and 
that  one  will  rather  be  satisfied  with  a  75  per  cent,  riveted 
joint,  of  which  one  can  see  the  details,  than  with  a  weld  which 
may  be  no  weld." 

International  Association  of  Steam  Users.  The  number  of 
3rd  October,  1908,  of  the  Gewerbeblatt  aus  Wurtemberg  states  : 

At  the  annual  Congress  at  Dantzig,  1907,  of  Delegates  and 
Engineers  of  the  International  Association  of  Steam  Users, 
embodying,  amongst  other  countries,  Austria,  Belgium, 
France,  Germany,  Italy  and  Switzerland,  it  was  resolved 
that  a  sum  of  2,000  marks  should  be  voted  for  testing  repairs 
by  autogenous  welding  upon  steam  boilers. 
•  The  technical  committee  of  the  Association  stipulated 
accordingly  that  samples  of  such  parts,  which  had  become 
defective  in  steam  boilers,  as  well  as  of  their  repairs  by  auto- 
genous welding,  should  be  sent  to  the  testing  institution  of 


EEPOETS  UPON  ACETYLENE   WELDING  249 

the  Royal  High  Technical  College,  Stuttgart,  which  had  been 
instructed  to  carry  out  said  tests. 

At  the  annual  Congress  at  Wiesbaden,  on  the  8th  and  9th 
September,  1908,  of  the  International  Association,  the  report 
of  such  tests  was  presented,  and,  after  discussion,  the  following 
resolution  was  unanimously  adopted  :— 

"  In  reference  to  repairs  on  steam  boilers  and  steam  vessels 
by  autogenous  welding  it  is  advisable  that  the  greatest  care 
should  be  exercised,  and  that  such  repairs  should  only  be 
entrusted  to  reliable  firms,  and  under  supervision  of  the 
respective  local  inspectors  of  the  Association.  Special  atten- 
tion should  be  given  to  such  parts  which  are  subjected  to 
tension  and  bending,  and  which  are,  by  heating  of  the 
surrounding  parts  of  the  weld  and  the  contraction  of  the 
filling  welding  material  (without  subsequent  annealing),  sub- 
jected to  tensions  which  may  cause  accidents  of  more  or  less 
severe  nature. 

"  Seams  which  are  exposed  to  the  influence  of  changeable 
temperatures  which  may  greatly  affect  tension  and  bending 
shall  only  be  welded  and  permitted  to  be  exposed  to  said 
influences  when  the  seam,  after  having  been  welded,  is 
subjected  to  annealing. 

"  The  above  resolution  is  left  to  the  earnest  consideration 
of  all  members  of  the  Association." 


CHAPTER  IX 


ACCIDENTS 

General — Explosive  Limits  of  a  Gas — Explosive  Limits  of  Acetylene — 
Danger  of  Acetylene  Installations — Prefect  of  Police,  Paris — Conseil 
d' Hygiene  Publique  et  de  Salubrite  Eegulations — Explosion  of 
Storage  Vessel  filled  with  Acetylene  Dissous :  Fatal  Result — Fire  at 
Acetylene  Dissous  Works — Bursting  of  Boiler  Tubes  caused  by 
Defective  Welding  :  Fatal  Eesult — Acetylene  Generator  Explosion — 
Acetylene  a  great  Poison — Acetylene  Accidents  in  France. 

WHEN  an  accident  has  taken  place  it  is  generally  too  late  to 
remember,  at  least  so  far  as  that  special  occurrence  is  con- 
cerned, that  acetylene  is  the  most  explosive  and,  therefore,  also 
the  most  dangerous  gas  yet  known,  when  dissolved,  more  so 
than  in  its  gaseous  form. 

The  explosive  limits  of  a  gas  and  the  range  of  explosibility 
are  influenced  by  various  circumstances,  such  as  manner  of 
ignition,  pressure  and  other  conditions.  Le  Chatelier  and 
Eitner  have  obtained  the  following  results  : — 

EXPLOSIVE  LIMITS  OF  ACETYLENE  MIXED  WITH  AIR 
CHATELIER). 


Diameter  of  Tube  in 
Millimetres. 

Explosive  Limits. 

Range  of 
Explosibility. 

Lower. 

Upper. 

Per  cent. 

Per  cent. 

Per  cent. 

40 

2-9 

64 

61-1 

30 

3-1 

62 

58-9 

20 

3-5 

55 

51-5 

6 

4-0 

40 

36-0 

4 

4-5 

25 

20-5 

2 

5-0 

15 

10-0 

0-8 

7'7 

10 

2-3 

0-5 

— 

— 

— 

ACCIDENTS 


251 


It  appears,  therefore,  that  no  explosion  of  acetylene  can 
proceed  past  an  orifice  of  0'5  m.m.  in  diameter. 

PERCENTAGE  BY  VOLUME  OF  COMBUSTIBLE  GAS  IN  A  MIXTURE  OF 
THAT  GAS  AND  AlR  CORRESPONDING  WITH  THE  EXPLOSIVE 
LIMITS  OF  SUCH  A  MIXTURE  (EITNER). 


Description  of  Combustible  Gas. 

Explosive  Limits. 

Difference  between 
Lower  and  Upper 
Limits,  showing 
range  covered  by 
the  Explosive 
Mixtures. 

Lower. 

Upper. 

Hydrogen 
Water-gas   (uncarburetted) 
Acetylene  .... 
Coal-gas    .... 

Per  cent. 

9-45 
12-70 
3-35 
7-90 

Per  cent. 

66-70 
66-75 
52-30 
19-10 

57-95 
54-35 
48-95 
11-20 

A  mixture  of  acetylene  and  air  becomes  thus  explosive  (will 
explode  if  a  light  is  applied  to  it)  when  only  3*35  per  cent,  of 
the  mixture  is  acetylene,  while  a  similar  mixture  of  coal-gas 
and  air  is  not  explosive  until  the  coal-gas  reaches  7*9  per  cent, 
of  the  mixture.  And,  again,  air  may  be  added  to  coal-gas, 
and  it  does  not  become  explosive  until  the  coal-gas  is  reduced 
to  19' 1  per  cent,  of  the  mixture ;  while,  on  the  contrary,  if  air 
is  added  to  acetylene,  the  mixture  becomes  explosive  as  soon 
as  the  acetylene  has  fallen  to  52'3  per  cent.  Hence  the 
immense  importance  of  taking  precautions  to  avoid,  on  the 
one  hand,  the  escape  of  acetylene  into  the  air  of  a  room,  and, 
on  the  other  hand,  the  admixture  of  air  with  the  acetylene  in 
any  vessel  containing  it  or  any  pipe  through  which  it  passes. 
These  precautions  are  far  more  essential  with  acetylene  than 
with  coal-gas. 

The  danger  is,  however,  materially  increased,  especially 
with  acetylene  installations  for  illuminating  purposes,  as 
they  are  generally  delivered  under  the  most  impressive 


252  WELDING  AND   CUTTING  METALS 

assurances  that  there  can  be  no  danger  whatever,  and 
under  that  impression  the  apparatus  is  left,  for  daily 
manipulation,  in  the  hands  of  persons  who  are  entirely 
ignorant  of  the  dangerous  nature  of  the  gas  and  the  construc- 
tion of  the  apparatus,  and  being  more  or  less  used  to  the 
easy  handling  of  the  ordinary  gas,  cannot  or  will  not  under- 
stand restrictions,  but  in  case  of  the  apparatus  getting  out  of 
order,  in  their  own  self-confidence,  and  with  the  best  inten- 
tions, take  steps  to  put  it  in  order,  which  may  have  serious 
results. 

It  is  easy  to  forget  that  by  placing  the  acetylene  apparatus 
in  the  house  a  more  or  less  dangerous  result  may  always  be 
expected,  so  also  by  careless  and  unskilled  manipulation  of  the 
plant,  or  by  natural  wear  and  tear,  or  by  corrosion  or  rust,  which 
scarcely  can  be  avoided,  or  by  using  inferior  material  in  order 
to  lower  cost  of  production,  all  of  which  will  sooner  or  later 
produce  leakage,  and  cause  an  explosion  as  soon  as  the  room, 
filled  with  the  extremely  small  quantity  of  acetylene  required,  is 
entered  with  a  light ;  or  the  gas  may  pass  into  another  room, 
where  a  candle  or  an  open  fire  is  burning,  causing  the  same 
result.  Consequently,  from  a  point  of  safety,  an  acetylene 
plant  can  only  thus  be  considered  free  from  danger  when  it  is 
placed  in  a  separate  house,  so  constructed  that  the  apparatus 
can  be  attended  to  from  outside ;  but  such  a  desire  can  scarcely 
be  fulfilled. 

The  Bulletin  des  Halles,  in  its  September  part,  1908,  states 
that  the  Prefect  of  'Police,  Pam,has,  upon  the  suggestions  of  the 
Conseil  d' Hygiene  publique  et  de  Salubrite,  circulated  additional 
regulations  in  reference  to  acetylene  generators,  amongst 
which  may  be  mentioned,  that  the  manipulation  necessary  for 
filling  and  emptying  the  generators  must  be  done  during  day- 
light. The  room  in  which  the  acetylene  plant  is  installed 
must  not  be  entered  with  light.  In  the  vicinity  of  the  door  to 


ACCIDENTS  253 

the  plant-room  must  be  affixed  in  a  visible  manner  a  board 
containing,  in  large  letters,  the  following  inscription  :  "  After 
the  daily  attendance  admittance  prohibited." 

Even  with  the  utmost  care  accidents  will  happen,  and  they 
will  more  forcibly  enforce  a  lesson  than  years  of  study.  For 
this  reason  the  following  accidents  are  related:  — 

Explosion  of  a  Storage  Vessel  filled  with  Acetylene-Dissous — 

Fatal  Result. 

Dr.  Paul  Wolff,  in  the  Zeitschrift  filr  Calcium  Carbid- 
Fabrikation,  Acetylene  und  Klein  Beleuchtimg,  No.  4,  1908, 
gives  the  description  as  follows  : — 

"  Unloading  cylinders  containing  acetylene-dissous  one  was 
suddenly  dropped,  falling  with  the  closing  valve  upon  the 
stone  pavement,  with  the  result  that  two  explosions  followed 
quickly,  one  after  the  other,  causing  great  injury  to  four 
persons,  one  of  which  succumbed  after  a  few  days." 

Fire  at  an  Acetylene-Dissous  Works. 

In  its  May  number,  1908,  the  Zeitschrift  fur  Comprimirte 
Gase  describes  the  fire  at  the  Acetylene-Dissous  Works  at 
Dose,  Qixhaven,  on  the  28th  May,  1908  :— 

"  The  Cuxhavener  Company  had  recently  acquired  a  system 
for  welding  by  acetylene-dissous,  probably  from  the  Compagnie 
Francaise  de  V Acetylene-Dissous.  On  the  day  of  the  accident 
an  engineer  of  the  said  French  company  was  filling  one  of  the 
cylinders,  under  a  pressure  of  fourteen  atmospheres,  and  having 
finished,  he  screwed  down  the  valve,  when  an  explosion  took 
place,  setting  fire  to  the  works.  He  had,  happily  enough, 
already  cut  off  the  connection  between  the  gas  generator  and 
the  filling  place,  otherwise  the  entire  works  would  have  been 
blown  to  pieces." 


254  WELDING  AND   CUTTING  METALS 

Dr.  H.  Rasch,  Geheimerat  (Technical  Councillor) ,  Hamburg, 
finishes  his  long  report  as  follows  :— 

"The  accident,  which  did  not  cost  any  life,  proves  that  the 
manufacture  of  the  compressed  acetylene-azetone  mixture 
must  be  attended  to  with  the  greatest  care.  The  pipings  must 
in  every  part,  especially  in  the  joints,  be  made  with  special 
care,  and  seamless  pipes  of  the  very  best  material  only  be 
used,  with  a  diameter  not  exceeding  9  m.m. 

"The  work  should  only  be  permitted  to  be  carried  out  under 
the  control  and  management  of  scientists  and  technically 
educated  persons. 

"The  accident  at  Dose  proves  that  explosions  are  constantly 
to  be  expected  when  the  cylinders  filled  with  the  acetylene- 
azetone  mixtures  are  exposed  to  fire." 

Bursting  of  Boiler  Tubes,  caused  by  Defective   Welding — 
Fatal  Result. 

In  part  7,  of  15th  April,  1908,  the  Z.  f.  Bayer- Revisions- 
Vereins  describes  the  fatal  accident  at  Forcheim  as  follows  :— 
"The  water-tube  steam  boiler,  300  q.m.  and  12  atm.,  was 
built  in  1900  by  the  firm  Petry  Dereux,  in  Diiren,  exhibited 
in  Paris  1900,  and  in  Diisseldorf  1902,  and  in  1903  installed 
in  its  present  place.  The  boiler  was  alternately  used  with 
an  active  one  to  feed  an  engine  of  800  h.p.  At  the  inspection 
of  28th  November,  1906,  and  14th  January,  1908,  the  boiler 
was  found  to  be  in  perfect  order.  On  Saturday,  15th  February, 
1908,  one  of  the  193  tubes  of  95  m.m.  diameter  burst  open  at 
a  steam  pressure  of  11  to  12  a  tin*,  emptying  the  boiler  in  eight 
minutes.  The  mixture  of  hot  water  and  steam  rushed  out 
through  the  damaged  tube,  between  the  fire-tubes  downwards 
over  the  grate,  pushing  open  the  fire-doors,  and  out  into 
the  fireplace,  scalding  the  stoker  and  his  assistant,  who 
nevertheless  were  able  to  go  to  the  porter's  house  at  a 


ACCIDENTS  255 

distance  of  almost  80  metres.     Both  succumbed  during  the 
night." 

According  to  the  report  and  the  unusual  situation  of  the 
crack  (on  one  of  the  upper  rear  end  tubes),  the  accident  was 
deemed  to  have  been  caused  by  a  defective  welding  of  the 
seam  of  the  tube.  It  is  known  that  defective  welds  of  tube 
seams  frequently  open  even  after  years  of  use. 

Acetylene  Explosion. 

The  Z.f.  Bayer.  Bev.-Ver.,  part  3,  of  29th  February,  1908, 
gives  the  report  of  the  explosion  of  an  acetylene  generator. 
The  installation,  made  in  the  autumn,  1906,  was  placed  in  a 
small  room  in  the  yard,  and  next  to  the  general  room  of  the 
hotel.  The  room  was  so  small  and  without  windows  that  the 
apparatus  could  only  be  attended  to  through  the  open  door, 
The  inspector  ordered,  however,  amongst  other  alterations, 
that  the  room  should  be  made  larger  and  be  provided  with  a 
window.  A  double  window,  15  c.m.  high  and  20  c.m.  wide,  was 
made.  The  generator  (Figs.  123  and  124)  of  the  carbide-to-water 
type,  with  a  capacity  of  5  kilogrammes  granulated  carbide, 
dropping  through  the  valve  V  into  the  generating  chamber  E. 
The  valve  rod  S  was  provided  with  a  packing  g  of  indiarubber 
in  the  lid  of  the  generator.  Between  the  generator  E  and  the 
gas-holder  B  is  the  water-safety  regulator  W,  protected  accord- 
ing to  regulations  against  frost,  and  behind  the  gas-holder  is 
the  purifier  R. 

On  the  5th  January,  1908,  at  7  p.m.,  the  light  was  bad. 
The  housemaid,  who  had  to  attend  to  the  apparatus,  went 
to  the  room,  pulling  the  lever  h  in  order  to  let  in  more  carbide 
into  the  generator.  The  water  was,  however,  frozen,  so  she 
tried  to  thaw  it  by  means  of  some  towels  dipped  in  hot  water. 
She  fetched  the  house-butcher  to  help  her,  and  probably 


256 


WELDING  AND   CUTTING  METALS 


placed  the  lamp  in  the  yard  about  3  to  4  metres  from  the 
door  of  the  installation  room.  The  butcher  commenced  with 
the  thawing,  while  the  girl  remained  just  behind  him,  when 
an  explosion,  although  very  small  and  soft,  took  place,  followed 
by  a  second  one,  much  stronger  and  more  sudden,  heaving  up 
the  generator.  The  girl,  and  especially  the  butcher,  were 
considerably  wounded,  with  their  hair  burnt  off.  A  carbide 


FIG.  123. 


FIG.  124. 


tin  and  the  lid  of  the  generator  were  fetched  out  by  fire-hooks. 
Neither  the  gas-holder  nor  the  purifier  were  destroyed,  but  the 
connection  between  the  generator  and  the  water  regulator  was 
blown  off,  and  the  rubber  packing  pushed  out  by  the  inner 
pressure.  The  small  sheet  soldered  to  the  centre  of  the  lid  of 
the  generator  was  melted  by  the  heat  and  destroyed,  and  the 
carbide  chamber  was  moved  away  and  destroyed.  The  rear 
end  of  the  house  was  damaged,  and  the  roof  was  raised.  On 
the  lid  of  the  generator  was  found  some  tallow,  spilt  from  a 


ACCIDENTS  257 

candle,  which  the  landlord  said  was  left  there  after  the 
explosion.  The  procedure  seems  to  have  been  as  follows  :— 

The  water  was  frozen ;  by  letting  more  carbide  drop  into 
the  generator  and  the  impossibility  for  the  gas  thus  generated 
to  reach  the  gas-holder  produced  a  greater  pressure,  pushing 
up  the  rubber  packing  and  permitting  thereby  the  gas  to 
escape  and  mix  itself  with  the  atmosphere,  igniting  in  the 
candle  light.  This  caused  the  first  explosion.  The  flame  then 
reached,  through  the  open  valve,  the  interior  of  the  generator, 
setting  fire  to  the  acetylene  contained  therein,  causing  the 
second  explosion. 

The  lesson  given  is  this  : — 

The  room  for  the  plant  was  exposed  to  a  freezing  tempera- 
ture, the  use  of  the  rubber,  a  most  unsatisfactory  packing 
material,  on  the  generator,  and,  in  spite  of  all  stipulations  to 
the  contrary,  the  use  of  a  bare  candle  light  in  the  room  of 
the  apparatus,  although  in  this  particular  case  the  light  was 
almost  indispensable  by  want  of  illumination  from  outside. 

The  case  is  further  instructive  in  this  respect,  that  the 
illumination  of  the  room  of  an  acetylene  plant  should  always 
be  arranged  from  outside,  especially  in  such  cases  where  the 
apparatus  must  be  attended  to  during  evenings  or  nights. 
This  refers  especially  to  private  houses,  and  more  so  where 
the  gas-holder  is  not  large  enough  to  take  the  greatest  quantity 
of  gas  required  during  the  night ;  this  is  always  the  case 
with  automatic  apparatus,  which  generally  have  too  small  a 
gas-holder. 

That  too  little  attention  is  given  to  the  construction  of  the 
room  for  acetylene  installations  is  a  well-known  fact,  particu- 
larly in  such  places  where  frost  may  be  expected.  The  walls, 
as  well  as  floors  and  roofs,  should  be  provided  with  spaces  for 
proper  insulation  by  peat  moss,  coal-dust,  or  other  similar 
insulating  materials ;  the  doors  should  be  made  from  double 

w.  s 


258  WELDING  AND  CUTTING  METALS 

wood,  and  when  possible  be  protected  from  the  east  and  north 
winds.  The  installation  of  special  heating  apparatus  can  only 
be  considered  for  central  or  large  installations.  A  well-known 
and  leading  acetylene  firm  prefers  even  to  build  separate 
installation  houses  with  insulating  walls  instead  of  using 
ordinary  brick  buildings  with  special  heating  apparatus.  See 
"Insulators,"  p.  57. 

Indiarubber,  like  glass,  belongs  to  that  kind  of  material 
which  should  never,  or  at  least  only  with  the  greatest  care,  be 
used  in  acetylene  installations,  and  never — as  in  the  case  just 
described — form  part  of  the  surface  of  an  acetylene  apparatus. 

To  the  professional  man  the  accident  above  mentioned  is  of 
particular  interest,  as  it  belongs  to  those  very  few  instances  of 
explosion  taking  place  in  the  interior  of  the  generator,  such 
accidents  occurring  generally  in  the  installation  room,  outside 
of  the  generator,  without  damaging  the  apparatus. 

Acetylene  a  Great  Poison. 

According  to  Z.f.  Calcmin-Carbid,  four  persons  inspected, 
from  pure  curiosity,  the  acetylene  apparatus  in  Schnear,  Biele- 
feld, and  noticing  some  unpleasant  smell,  they  soon  left  the 
room.  Having  taken  ten  to  fifteen  minutes'  walk  in  the  fresh 
air,  they  all  four  fell  down  unconscious ;  medical  aid  was  soon 
available,  and  after  their  recovery  the  doctors  explained  the 
highly  poisonous  nature  of  the  acetylene  gas  and  its  dangerous 
and  speedy  effect  upon  human  life. 

In  its  number  of  October  3rd,  1908,  Revue  des  Edairages 
states  that  ten  to  twelve  acetylene  accidents  are  generally 
reported  every  month,  making  about  130  a  year.  There  are 
13,000  acetylene  installations  in  France  inspected  by  the 
Union  des  Proprietaries  d'Appareils  d  Acetylene. 


CHAPTEE   X 

LEGISLATION 

Order  of  Council  re.  Petroleum  Acts — Order  in  Council  re  Explosives 
Acts— Home  Office  Conditions  for  Acetylene  Generators — English 
Acetylene  Associations'  Regulations. 

Legislation  relating  to  Calcic  Carbide  and  Acetylene. 

EAELY  in  1897  an  Order  of  Council  was  issued  placing  car- 
bide of  calcium  under  the  Petroleum  Acts,  not  with  any 
intention  of  hampering  the  industry,  but  with  the  object  of 
bringing  before  the  notice  of  the  public  that  in  the  use  of  the 
new  illuminant,  acetylene,  and  in  the  employment  of  carbide 
of  calcium,  from  which  it  is  evolved,  reasonable  precautions 
would  have  to  be  taken.  This  action  of  the  Home  Department 
cannot  be  too  strongly  commended,  and  if  it  seems  to  some 
that  it  may  have  retarded  the  development  of  the  industry,  it 
must  also  be  borne  in  mind  that  the  injury  of  persons  by 
avoidable  accidents  would  have  retarded  it  still  more,  and  it  is 
satisfactory  to  note  that  in  this  country  we  have  not  had  to 
deplore  such  accidents  as  have  occurred  abroad.  It  is  true 
that  these  accidents  were  chiefly  due  to  the  storage  of  liquefied 
acetylene  in  cylinders  under  very  high  pressures,  the  use  of 
which  is  prohibited  in  this  country,  still,  but  for  legislation, 
similar  accidents  would  probably  have  occurred  here. 

The  public,  hearing  of  these  accidents  through  the  Press, 
could  not  of  course  be  expected  to  distinguish  between  liquid 
acetylene,  stored  at  a  pressure  of  700  Ibs.  to  the  square  inch,  and 
gaseous  acetylene  at  low  pressure,  which  with  ordinary 

s  2 


260  WELDING  AND   CUTTING  METALS 

care  can  be  quite  safely  generated  in  properly  constructed 
apparatus. 

By  an  Order  in  Council  of  November,  1897,  acetylene  gas,  when 
liquid  or  when  highly  compressed,  was  very  properly  brought 
under  the  Explosives  Acts,  but  with  the  proviso  that  if  it  could 
be  shown  to  the  satisfaction  of  the  Secretary  of  State  that 
acetylene  in  any  form  or  condition  was  not  explosive,  an 
exemption  might  be  granted. 

Exemption  was  subsequently  granted  for  certain  admixtures 
of  acetylene  and  oil- gas  on  the  initiative  of  the  Acetylene 
Illuminating  Company. 

British  Home  Office  Committee  of  1901,  dealing  ivith  the  condi- 
tions which  an  Acetylene  Generator  should  fulfil  before  it 
can  be  considered  as  being  safe. 

1.  The  temperature  in  any  part  of  the  generator,  when  run 
at  the  maximum  rate  for  which  it  is  designed,  for  a  prolonged 
period,  should  not  exceed  130°  C.     This  may  be  ascertained  by 
placing  short  lengths  of  wire,  drawn  from  fusible  metal,  in 
those  parts  of   the  apparatus  in  which  heat  is  liable  to  be 
generated. 

2.  The  generator  should  have  an  efficiency  of  not  less  than 
90   per   cent,  which,  with  carbide  yielding  5  cubic  feet  per 
pound,  would  imply  a  yield  of  4'5  cubic  feet  per  each  pound  of 
carbide  used. 

3.  The  size  of  the  pipes  carrying  the  gas  should  be  propor- 
tioned to  the  maximum  rate  of  generation,  so  that  undue  back 
pressure  from  throttling  may  not  occur. 

4.  The  carbide   should  be  completely  decomposed  in  the 
apparatus  so  that  lime  sludge  discharged  from  the  generator 
shall  not  be  capable  of  generating  more  gas. 

5.  The  pressure  in  any  part  of  the  apparatus,  on  the  gene- 
rator side  of  the  holder,  should  not  exceed  that  of  20  ins.    f 


LEGISLATION  261 

water,  and  on  the  service  side  of  same,  or  where  no  gas-holder 
is  provided,  should  not  exceed  that  of  5  ins.  of  water. 

6.  The  apparatus  should  give  no  tarry  or  other  heavy  con- 
densation products  from  the  decomposition  of  the  carbide. 

7.  In  the  use  of  a  generator  regard  should  he  had  to  the 
danger  of  stoppage  of  passage  of  the  gas  and  resulting  increase 
of  pressure  which  may  arise  from  the  freezing  of  the  water. 
Where  freezing  may  be  anticipated  steps  should  be  taken  to 
prevent  it. 

8.  The  apparatus    should  be  so  constructed  that  no  lime 
sludge  can  gain  access  to  any  pipes  intended  for  the  passage 
of  gas  or  circulating  of  water. 

9.  The  use  of   glass  gauges  should  be  avoided  as  far  as 
possible,   and,  where   absolutely  necessary,  they   should    be 
effectively  protected  against  breakage. 

10.  The  air  space  in  a  generator  before  charging  should  be 
as  small  as  possible. 

11.  The  use  of  copper  should  be  avoided  in  such  parts  of 
the  apparatus  as  are  liable  to  come  in  contact  with  acetjdene.* 

The  English  Acetylene  Associationh&s  drawn  up  the  following 
list  of  regulations,  which  it  suggests  shall  govern  the  construc- 
tion of  generators  :— 

1.  The  temperature  of  the  gas  immediately  on  having  the 
charge  shall  not  exceed  212°  F.  (100°  C.). 

2.  Machines   shall   be  so  constructed  that  when   used   in 
accordance  with  printed  instructions  it  shall  not  be  possible 
for  any  undecomposed  carbide  to  remain  in  the  sludge  removed 
from  the  generator. 

3.  The  limit  of  pressure  in  any  part  of  the  generator  shall 
not  exceed  that  of  20  ins.  of  water,  subject  to  the  exception 
that  if  it  be  shown  to  the  satisfaction  of  the  Executive  of  the 
Acetylene    Association  that  higher  pressures,    up   to  50  ins. 

*  This  refers  evidently  to  pure  copper  and  not  to  its  alloys. — Author. 


262  WELDING  AND   CUTTING  METALS 

of  water,  are  necessary  in  certain  generators  and  without 
danger,  the  Executive  may,  with  the  approval  of  the  Home 
Office,  grant  exemptions  for  such  generators,  with  or  without 
conditions. 

4.  The  limit  of  pressure  in  service  pipes  within  the  house 
shall   not    exceed  5  ins.   of  water,    subject  to  the  exception 
that  if  it  be  shown  to  the  satisfaction  of  the  Acetylene  Associa- 
tion   that  for    certain   purposes    a    higher  pressure,    up   to 
10  ins.  of  water,  is  necessary,  the  Executive  may  authorise 
such  higher  pressure  to  be  used  for  such  purposes. 

5.  The  apparatus  shall  give  no  tarry  or  other  heavy  con- 
densation products  from  the  decomposition  of  the  carbide. 

6.  In  the  use  of  a  generator  regard  shall  be  had  to  the 
danger  of  stoppage  of  passage  of  the  gas  and  resulting  increase 
of  pressure  which  may. arise  from  the  freezing  of  the  water. 
Where  freezing  may  be  anticipated  steps  shall  be  taken  to 
prevent  it. 

7.  It  shall  not  be  possible  under  any  conditions,  even  by 
wrong  manipulation  of  cocks,  to  seal  the  generating  chamber 
hermetically. 

8.  It  shall  not  be  possible  for  the  lime  sludge  to  choke  any 
of  the  gas-pipes  in  the  apparatus  nor  water-pipes,  if  such  be 
alternately  used  as  safety-valves. 

9.  The  use  of  glass  gauges  shall  be  avoided  as  far  as  possible, 
and  where  absolutely  necessary  they  shall  be  effectively  pro- 
tected against  breakage. 

10.  The  air  space  in  the  generator  before  charging  shall  be 
as  small  as  possible,  i.e.,  the  gas  in  the  generating  chamber 
shall  not  contain  more  than  8  per  cent,  of  air  half  a  minute 
after  commencement  of  generation.     A  sample  of  the  contents 
drawn  from  the  holder,  any  time  after  generation  has  com- 
menced, shall  not  contain    an  explosive  mixture,  i.e.,  more 
than  18  per  cent,  of  air.     This  shall  not  apply  to  the  initial 


LEGISLATION  263 

charges  of  the  gas-holder,  when  reasonable  precautions  are 
necessary. 

11.  Generators  and  apparatus  shall  be  made  of  sufficiently 
strong  material  and  of  good  workmanship,  and  shall  not  in 
any  part  be  constructed  of  unalloyed  copper. 

12.  Generators   shall   have   sufficient   storage   capacity   to 
make  a  serious  blow-off  impossible. 

13.  Wherever   the  generating   plant  is  situated    sufficient 
ventilation  must  always  be  provided. 

A  blow-off  pipe  shall,  wherever  desirable,  be  affixed  leading 
from  the  gas-holder  to  the  open  air. 

14.  The  Association  strongly  advise  the  use  of  an  efficient 
purifier  with  generating  plant  for  indoor  lighting. 

15.  No  generator  shall  be  sold  without  a  card  of  instructions 
suitable  for  hanging  up  in   some  convenient   place.      Such 
instructions  shall  be  of  the  most   detailed  nature,  and  shall 
not  presuppose  any  expert  knowledge  whatever  on  the  part  of 
the  operator. 

16.  Every  generator  shall  have  marked  clearly  upon  the 
outside  a  statement  of  the  maximum  number  of  half-cubic- 
foot  burners  and  the  charge  of  carbide  for  which  it  is  designed. 


CHAPTER  XI 

USEFUL    ADDENDA 

British  Thermal  Unit— Combustion  of  Carbon,  Acetylene,  Hydrogen, 
and  Coal  Gas — Coefficient  of  Heat — Consumption  of  Combustible 
Gases — Pressure,  Weight,  and  Volume  of  Air — Temperature  of 
Fusion,  Metric  and  English  Measures. 

British  Thermal  Unit  is  the  amount  of  heat  required  to 
raise  the  temperature  of  1  Ib.  of  water  at  32°  Fahr.  1°  Fahr. 

On  the  continent  of  Europe  the  caloric  is  used,  and  the 
standard  is  the  heat  required  to  raise  the  temperature  of 
one  kilogramme  of  water  one  degree  Centigrade. 

To  convert  British  thermal  units  per  pound  of  coal  into 
calories  per  kilogramme  of  coal,  multiply  by  5  and  divide 
by  9. 

Combustion  of  1  Ib.  of  carbon  requires  2*66  Ib.  oxygen,  and 
as  the  atmospheric  air  contains  only  23  per  cent,  of  oxygen, 
it  follows  that  11*6  Ibs.  of  air  are  necessary  for  the 
combustion  of  1  Ib.  of  carbon. 

One  volume  of  acetylene  requires  theoretically  2J  volumes 
of  oxygen  for  complete  combustion,  but  with  a  satisfactory 
blowpipe  the  best  welding  results  are  obtained  with  T7  volumes 
of  oxygen  to  one  volume  of  acetylene. 

Two  volumes  of  hydrogen  require  one  volume  of  oxygen  for 
complete  combustion,  but  in  order  to  ensure  a  non-oxidising 
flame  the  gases  must  be  burned  in  the  proportion  of  about 
four  volumes  of  hydrogen  to  one  volume  of  oxygen. 

One  volume  of  coal-gas  requires  about  1'25  volume  of 
oxygen  for  combustion,  but  for  general  purposes  about  1*33 
volume  of  oxygen  is  used. 


USEFUL  ADDENDA  265 

COEFFICIENT  OF  HEAT. 

Conductivity  in  Calories  : — 

Copper      .  .  330*00  Water  .  .  0'77 

Iron.         .  .  40-00  Cement  .  .  0'059 

Masonry    .  .  T6  Air    .  .  .  0'0175 

Firebrick  .  .  0*7 

COMBUSTIBLE  GASES. 

The  consumption  of  liquefied  and  compressed  gases  during 
1906  is  given  as  follows  : — 

Belgium  .  100,000  cubic  metres  =      3,500,000  cubic  feet. 

England  .  150,000  „  =      5,250,000 

France     .  300,000  „  =  10,500,000 

Germany  400,000  „  ==  14,000,000 

It  is  interesting  to  note  the  steady  and  enormous  increase 
in  the  consumption  of  liquefied  and  compressed  gases  in 
Germany,  given  as  follows  :— 

1899  .  175,000  cubic  feet.  1903  .  1,750,000  cubic  feet. 

1900  .  350,000        „  1904  .  3,150,000 

1901  .  525,000        „  1905  .  4,200,000 

1902  .  1,225,000        „  1906  .  14,000,000 

Such  an  enormous  annual  increase  in  the  production  of 
liquefied  and  compressed  gases,  and  their  subsequent  applica- 
tion for  industrial  purposes,  as  already  indicated,  is  a  proof  so 
complete  that  the  nature  of  enquiry  cannot  be  touched  by 
criticism  ;  nevertheless,  there  is  still  room  for  improvement 
and  for  new  fields  to  be  found  for  their  practical  application. 

Pressure. 

One  Atmosphere  =  14*7  Ibs.  per  square  inch  =  2116*35  Ibs. 
per  square  foot ;  =  33'90  feet  of  water ;  =  1'033  kilogrammes 
per  square  centimetre  =  760  m.m.  of  mercury. 


266  WELDING  AND   CUTTING  METALS 

Weight  and  Volume  of  Air. 

A  cubic  foot  of  air  at  60°  and  under  average  atmospheric 
pressure,  at  sea  level,  weighs  536  grains  ;  and  13*06  cubic  feet 
weigh  1  Ib. 

Air  expands  or  contracts  an  equal  amount  with  each  degree 
of  variation  in  temperature. 

Temperature  of  Fusion. 

Tin,  455°;  bismuth,  518°;  lead,  610°;  aluminium,  850°; 
zinc,  700°;  antimony,  810°;  brass,  1,650°;  silver,  pure, 
1,830°;  gold  coin,  2,156°;  iron,  cast,  2,010°;  steel,  2,250°; 
and  wrought  iron,  2,910°  Fahr. 

Conversion. 

9 

Fahrenheit  =   '-  (Centigrade  +  32). 
o 

Centigrade  =  |   (Fahrenheit  -  32). 

METRIC  AND   ENGLISH  MEASURES, 
AS  COMPILED  AND  PUBLISHED  BY  P.  E.  PVADLEY. 

Reciprocals  for  Rapid  Approximate  Calculations. 

Centimetres  to  inches         .         .         .         .  -f-  2 

Cubic  centimetres  to  cubic  inches     .         .         .  X  6  -r-  100 

,,  ,,  to  gallons     ....  X  '00022 

,,      inches  to  cubic  centimetres     .         .         .  -f-  16| 

,,      metres  to  cubic  feet         .         .         :  X  35^ 

inches     ....  X  6102 

yards       .         .         .         .  X  13  -f-  10 

Feet  to  metres .  -r  3 

Gallons  to  cubic  centimetres     ....  X  4546'69 

,,        to  litres X  4j 

Grains  to  grammes    .         .         .         .         .         .X  '065 

Grammes  to  grains    .         .         .         .         .         .  X  15'43 

Inches  to  centimetres        .         .         .         .  X  2 


USEFUL  ADDENDA 


267 


Inches   to  metres 
,,       to  millimetres 
,,       Fractions  ^  to  millimetres 

TV 
,. 

TV 


Kilogrammes  to  hundredweights 

,,  to  pounds    . 

Litres  to  gallons  (Imperial) 

,,       to  pints  . 
Metres  to  feet    . 
,  ,       to  inches        . 
,,       to  yards          .         .         . 
Millimetres  to  inches         .         . 
.,  ,,  fractions  ^ 

„  TV 

„  TV 


„       *    - 

Pints  to  cubic  centimetres 
,,      to  litres  . 

Pounds  to  hectogrammes  . 
,,        to  kilogrammes     . 

Square  centimetres  to  square  inches 
,  ,      feet  to  square  metres     . 
,,      inches  to  square  centimetres 
,,          ,,       to      ,,       metres 
,,      metres          ,,       feet 
,,          ,,  ,,       inches 

.,          ,,  ,,       yards  . 

,,      yards  to  square  metres  . 

Yards  to  kilometres  . 
to  metres 


'0254 


8-5-10 


X 
X 
X 
X  1£ 
X  2 
X  2£ 
X  3 
X6| 
X  8£ 
X  12| 
X  '0197 
X  22 


10 
100 


22  -5- 
If 


11  -5-  10 
4  -r-  100 
1J 

6  -5-  10 


X  4  -T-  10 
X  3  -MO 
X  16  4-  100 
X  12  4-  100 
X  8  -r  100 
X  568J 
Hh"2 


4|  -v-  10 
15  -r-  100 

9  -5-  100 


X 

X 

X 

X  6£ 

X  61  H-  10,000 

X  lOf 

X  1,550 

X  12-5-  10 

X  8-5-  10 


X  9  -t-  10,000 


INDEX 


A. 


ACCIDENTS,  248 
Acetone,  58,  152 
Acetylene,  9,  53 
blowpipes,  152 
burners,  16 
caloric  value,  20 
combustion,  152,  264 
committee  of  Eoyal  Society  of 

Arts,  10 

compressed,  9,  58,  250 
corrosive  nature,  15 
cylinders  for,  45 
danger  of,  10,  15,  143,  251 
decomposition  of,  10,  16 
description,  9 
dissolved  (dissous),  8,  58 
English    Acetylene     Associa- 
tion's regulations,  261 
explosions,  53,  251 
explosive  nature  with  air,  10, 

250 
copper, 

10 
compressed, 

250 

limit,  21,  250 
range,  10,  250 
flame,  composition  of,  164 
generators,  10,  16,  40,  51,  58 

explosion,  18,  255 
Home  Office  Eegulations,  58, 

260 

Illuminating   Company,  Ltd., 
7,  59,  153 


Acetylene — continued. 
impurities,  16 
Journal      ("  The      Lighting 

Journal"),  7 
leak  tester,  44 
liquefaction,  9 
poisonous  nature,  16,  258 
polymerisation,  16 
Eoyal  Society  of  Arts,  10 
temperature,  164 
welding  plant,  low  pressure, 

40,  162 
high  pressure, 

40,  58 
report,  236 

versus  hydrogen  weld- 
ing, 142 
riveting,  225 
Acogine,  50 
Addenda,  useful,  262 
Aeriform,  5 
Aggregation,  5 
Air,  atmospheric,  6 

diphlogisticated.  23 
liquefied,  6 

Allgemeine  Elektr.  Gesellschaft,  70 
Alloys,  welding  of,  2 
Aluminium  welding,  61 
Alumino-thermic  process,  67 
Andrews,  Thomas,  F.E.S.,  6 
Annealing  of  cylinders,  46 

welds,  243 
Ansdell,  9 

Armour  plates,  cutting  of,  113,  232 
Arsenal,  Imperial,  Dantzig,  172 
Articles  of  difficult  form,  174 


270 


INDEX 


Atmospheric  air,  6,  265 

liquefaction  of,  6 
Australasian     Steam     Navigation 

Company,  Sydney,  220 
Autogenous  welding,  2,  39,  197 
Automatic    law   pressure    welding 

plant,  51 


B. 


BADISCHE  Anilin  and  Soda  Fabrik, 

22 

Bar,  welding,  3 
Bassanis  density  meter,  30 
Bausingault  process,  25 
Bayerischer  Revisions  Yerein,  244, 

254 
Belgium  Steam  Users'  Association, 

248 
Benzene  in  acetylene,  16 

air  required  for  combus- 
tion, 16 
Berlin  Gross  Lichterfelde,  welding 

of  rails,  70 

Bernados  electr.  process,  89 
Berthelot,  9 

Blacksmith  and  anvils,  1 
Blau  gas,  19 
calorics,  20 
composition,  20 
explosive  nature,  range  of,  21 
welding,  82 
Blowpipes,  148 

Acetylene    Illuminating    Co. , 

Ltd.,  153 
brazing,  85,  113 
British  Oxygen  Co.,  Ltd.,  85 
Brussel,  van  J.  B.,  232 
conditions  of,  148,  241 
Draeger-Wiss,  149 
economy  of,  146 
Fouche,  153,  158 
general,  148 
high  pressure,  153 


Blowpipes — continued. 

Jottrand-Lulli,  139,  149 
lead  burning,  83 
low  pressure,  154 
Board  of  Trade,  125,  260 
Boiler  maker,  196,  225 

welded,  advantages  of,  193 
Boyle,  Eobert,  F.K.S.,  24 
Brazing,  82,  113 
Brin's  oxygen  process,  25,  33 
British  Government  Cylinder  Com- 
mittee, 46 

British  Institute  of  Marine  Engi- 
neers, 201 
Liquid  Air  Company,  Ltd., 

32 
Oxygen  Company,  Ltd.,  25, 

32,  45,  82 
Steam  Users'   Association, 

221 

Bulletin  des  Halles,  252 
Burners,  acetylene  apt  to  smoke,  16 
Butterfield  and  Leeds,  49 
Biilow,  C.  E.,  219 


C. 

CAGNIARD  de  la  Tour,  5 
Cailletet,  Louis,  7,  9,  22 
Calorific  value  of  acetylene,  20 
Blau  gas,  20 
coal  gas,  87 
hydrogen,  21 
water  gas,  33 
Carbide  of  calcium,  7 
decomposition,  14 
density,  15 
description  of,  7 
deterioration  of,  8 
explosive  nature,  9,  14 
legislation,  259 
moisture  in,  8 
receptacle  for,  8 
storage  of,  8 


INDEX 


271 


Carbide  of  calcium — continued. 
yield  of  gas,  8,  15,  54 

slaked  lime,  1 5,  19 
space  occupied  by  given  weight, 

15 

volume  of  gas  evolved,  14,  54 
lime  formed  by  de- 
composition, 15 
weight  of,  15,  55 
Zeitschrift,  253,  258 
Carbon, 

influence  on  welding,  4,  89 
Carburation,  3 
Cartvale  flake  charcoal,  57 
Cast  iron  pipes,  97,  110,  168,  171 
Casting,  welding,  3 
Caution  re  use  of  copper,  10 

oil,  44 

Charcoal  insulator,  57 
Chatelier,  L.,  221 
Chemical  welding,  86 
Chemische  Fabrik  Griesheim  Elek- 

tron,  22,  234,  243 
Claude,  Eugene,  7,  32 
Claude  and  Hess,  9,  152 
Clowes,  Dr.  Frank,  10 
Coal  gas,  87 

blowpipes,  85 
calorific  value,  20 
combustion,  152,  264 
explosive  nature,  range  of,  252 
welding,  87 
Coefficient  of  heat,  265 
Coffin  electr.  weld,  process,  89 
Combustible  gases,  3,  252,  265 
Combustion  of  acetylene,  21,  264 
benzene,  16 
Blau  gas,  16 
coal  gas,  21,  264 
hydrogen,  264 
water  gas,  33 
Committee    of    Royal    Society    of 

Arts,  10 

Compagnie  des  Messageries  Mari- 
times,  247 


Compagnie  Frangaise  de  1'Acety- 

lene-Dissous,  253 

Comparative  cost  of  acetylene  and 

hydrogen 

welding,  142 

iron  and  steel 

pipes,  181 
welded      and 
riveted 
tanks,   195, 
225 

Comparative  corrosion  of  wrought 
iron,  soft  steel,  and  nickel  steel, 
188 

Compressed  gases,  24,  49,  232 
|  Comptes  Eendus,  22 
Conditions    for    producing    proper 

welds,  3 

Conductor  rails,  welding  of,  69 
Congress  of  Dantzig,  248 
Liege,  229 
Wiesbaden,  249 
Conseil  d'Hygiene  publique  et  de 

Salubrite,  252 

Consumption  of  acetylene  for  weld- 
ing, 153 
coal  gas,  152 
gases   for    cutting 

metals,  229 
hydrogen,  139 
oxygen,  139,  152 
Continuous  rails,  70 
Copper, 

forming    an    explosive    with 

acetylene,  10 
welding  of,  87 
Corrosion,  192,  198 
acetylene,  15 
internal,  199 
marine  boilers,  198 
nickel  steel,  188 
outside,  198 
soft  steel,  188 
steam  boilers,  192,  195 
wrought  iron,  188 


272 


INDEX 


Cost  of  cast-iron  and  riveted  pipes, 

180 
labour    and     material    for 

tubular  boilers,  196 
riveting  v.  welding,  225 
Coventry  Electric    Tramways   Co. 

tests,  75 

Critical  density,  6 
point,  6 
pressure,  6 
temperature,  6 
volume,  6 
Cutting  metals,  229 
Cuxhavener  Company,  253 
Cylinders,  45 

annealing  of,  46 
Committee  of  British  Govern- 
ment, 46 

compressed  gases  for,  45 
proving  of,  45 
size  of,  45 
stands  for,  45 
stretch  testing  apparatus  for, 

46 

tests  of,  45 
valves  for,  41 


D. 


DANTZIG,  Congress  of,  248 

Imperial  Arsenal,  172 
Davy,  Sir  Humphry,  F.K.S.,  5 
De  Meritens,  88 

Decomposition  of  acetylene,  explo- 
sive violence,  10,  16 
Density,  critical,  6 

of  carbide  of  calcium,  15 
meter  (Bassani's  elec.), 

30 
Department     of      Public     Works, 

Victoria,  185,  186 
Dephlogisticated  air,  23 
Dereux,  Petry,  Diiren,  254 
Deterioration  of  calcium  carbide,  8 
Deutsche  Oxhydric  Company,  233 


Deutsche  Solway  Werke,  22 
Dewar,  Sir  James,  7,  24 
Diaphragms  of  conductingmaterial, 
for     electrolysis     of 
water,  26 
metallic,  27 
non-conducting,  26 
perforated,  28 
porous,  26 
size  of,  28 
Dingler's  Polytechnisches  Journal, 

221,  236 

Disadvantages  of  welding  on  steam- 
boilers,  194 

Dissolved  acetylene,  8,  58 
Draeger-Wiss  blowpipes,  149 

pump  for  compressed 
gases,  49 


E. 


ELASTIC  limit,  47 
Electric  arc,  88 
current  in,  90 
electrodes,  89 

energy  for  welding  copper,  92 
iron,  89 
steel,  89 
poles  of,  89 
potential,  89,  90 
resistance,  88 
temperature,  90 
Electric  density  meter,  30 

energy    for    welding,    89, 

103,  113 
brass,  114 
copper,  111,  114 
iron,  111,  114 
steel,  111,  114 
pressure  to  complete  weld, 

92 

resistance,  91 
transformers,  93,  112 
weld,  finishing  of,  92 


INDEX 


273 


Electric  Welding  Company,   Ltd., 

Ill 

Electric  welding,  88 
cost  of,  88 
generators,  91 
welding  machines,  91 
direct  welder,  93 
special,  93,  97 
standard  types  of,  111 
transformers,  93,  112 
types  of,  111 
universal,  93 
for  automobiles,  98,  109, 

118,  123 

baby  carriages,  123 
bends,  97,  111,  127, 

132 

bicycles,  98,  109,  123 
bolts,       square       and 

hexagon,  118 
bosses  for  drain  pipes, 

129 

buckles,  97,  102 
chains,    all    sizes,    97, 

111,  119,  137 
clock  making,  98,  106 
coils  for  refrigerating, 

122 

cost  of,  136 
crank  shafts,  118 
cutlery,   hollow- 
handled,  116,  123 
cycles,  98,  109,  123 
cylinders,  123 
door  hinges,  97,  104 
drain  pockets,  129 
fittings,  130 
flanges,  124 
forming  joints  in  thin 

material,  115 
frames,  111 
harness  rings,  120 
hinge  bands,  97,  104 
hooks,  97,  104 
hoops,  97, 105, 109,  111 
w. 


Electric  welding — continued. 

welding  machines — continued. 
for  iron  furniture,  98 
lead,  110 

mains,     electric,     gas 
and  water,  97,  110, 
122,  124,  129 
pipes  and   tubes,    97, 

110,  122,  124,  129 
plant  of,  212 
point-welding,  98,  107 
pulley  and  spokes  to 
rim,  98,  108, 
115 
window  sashes, 

115 

rails,  69,  135 
receivers,  132 
rings,  97,  105,  120 
simultaneous   welding 
of  pins  and  pieces  to 
discs,  97 
spiral  of  iron  tubing, 

122 
steam  dryers,  137 

gauges  and 
thermometers, 
welded  to  pipes, 
131 

switchboard,  119 
tubes,  97 
tyres,  123 
water  mains,  137 
wires   and  wire    net- 
tings,97,lll,117, 120 
Electric  welding  processes,  88 
arc  processes,  88 
Bernados,  89 
Coffin,  89 
De  Meriten,  88 
Haho  and  Legrange,  90 
Olszewski,  89 
Slavianoff,  89 
Werderman,  90 
Zerener,  90 


274 


INDEX 


Electric    welding    processes — con- 
tinued. 

resistance  processes : 
Elihu  Thomson,  91 
Helberger,  92 
Lemp,  113 

Electrical  Times,  114 
Electrolysis  of  water,  25 
diaphragms,  27 
electrodes,  27,  30 
electrolyte,  27,  29 
electromotive  force,  27 
gases  evolved,  27,  30 

separation  of,  26 
processes  by : 
Garuti,  26 

Hasard  Flamand,  26 
Kenard,  26 
Schmidt,  26 
Schuckert,  26 

End-to-end  welding,  97,  105 
Endothermic  compounds,  9 
English     Acetylene     Association's 

regulations  for  generators,  260 
Engineering  Magazine,  232 
Engineering  Standard  Committee, 

125 

Evaporation  of  oxygen,  24 
Ewing,  Professor,  F.E.S.,  57 
Examination,     microphotographic, 

63 

microscopical,      of 
welded  metals,  4 
Exothermic  compounds,  9 
Expansion  of  gases,  24 
Explosion,  range  of  for  acetylene, 
10,21,251 
Blau  gas, 

21 
coal-gas, 

21,  252 
hydrogen, 

22,  252 
water-gas, 

252 


Explosive  gas,  22,  31 

acetylene  generator,  18,  255 
dissous,  storage  vessel,  253 

works,  253 
Acts  applied  to  acetylene  gas, 

260 
calcium  carbide, 

259 

boiler  tubes,  254 
defective  weld,  254 
mixture  of  acetylene,  10,  251 
violence  of  acetylene,  18,  251 

F. 

FAHNEHJELMS  combs,  34 
Falls  of  Foyers,  7 
Faraday,  Michael,  F.E.S.,  5 
Ferguson,  Mephan,  179 

pipes  in  various  countries,  183 
Fertiliser  obtained  from  acetylene, 

8 

Fitzner,  W.,  169 
Flame,  2 

carbonising,  4 

decomposition,  242 

form,  164 

neutral,  4 

oxidising,  4,  144 

poisoning,  145 

reducing,  4,  144 

temperature,  151,  164 
Flux  for  welding,  87 
Forging  of  iron  and  steel,  39,  113, 

138 

Fouche"  blowpipes,  153,  158,  234 
Foyers,  Falls  of,  7 
Frankoline,  50 
French  Steam    Users'   Association 

("Veritas"),  247 
Fusion  of  metals,  39,  266 

G 

GARUTI,  P.,  Professor,  26 
Gas,  combustible,  36,  251,  265 


INDEX 


275 


Gas  combustion,  36 

compressed,  24,  192,  231,  252 

expansion,  24 

liquefaction  of,  5 

permanent,  6 
Gaseous  state,  5 

Gases  and  sources  for  their  genera- 
tion, 5 

Gay-Lussac,  24 
General  remarks,  1 
Generators  for  acetylene,  10,  51 

Blau  gas,  19 

electric  welding,  88 

hydrogen,  25 

oxygen,  25,  33 

water-gas,  33,  168 
Gerard,  Eric,  Professor,  30 
German  Steam  Boilers  Association, 

221 

Gewerbeblatt  aus  Wurtemberg,  248 
Green,  E.  &  H.,  220 
Griesheim  Elektron,  Chem.  Fabrik, 
22,  234,  243 

H. 

HAHO  and  Legrange,  90 

Halifax  Borough,  tests,  74 

Hartmann,  C.  L.  J.,  report,  244 

Hasard  Elamand,  26 

Heap,  removing  of,  by  the  blow- 
pipe, 192 

Helberger,  Hugo,  92 

Helbronner,  Andre,  7 

Ilempel's  gas  analysing  apparatus, 
30 

Heraeus,  W.  C.,  61 

Heratol,  50 

Hess  and  Claude,  compressed  acety- 
lene, 9,  52 

Heterogeneous  welding,  39 

Heylandt,  7 

High  pressure  automatic  regulator, 

43 

blowpipe,  148 
oxy-acetylene  welding  plant,  58 


Hilpert,  Dr.,  221,  236,  247 
Home  Office, 

conditions  for  acetylene  gene- 
rators, 58,  260 

Explosives  Acts,  260 

Petroleum  Acts,  259 
Howe,  Professor,  188 
Humboldt,  Alexander  von,  24 
Hydraulic  pressure  regulator,  41 

testing  of  cylinders,  46 
Hydrogen,  21 

blowpipes,  178,  229 

caloric  value,  21 

consumption,  230,  252,  264 

cutting  metals,  229 

description,  21 

explosion,  range  of,  22,  252 

generators,  25 

inhalation,  22 

liquefaction,  22 

pressure    for    cutting   metals, 
232 

relative       advantage       versus 
acetylene  welding,  142 

welding,  139,  197 

I. 

IGNITION  of  undecomposed  carbide, 

14 
Imperial  Arsenal  of  Dantzig,  tests, 

172 

Institute,     exhibition    of 
acetylene  generators,  10 
India,  184 

Inhalation  of  hydrogen,  22 
Inspector- General  of  Public  Works, 

Victoria,  182 

Inspectors,  Steam  Users'  Associa- 
tions, 221 
Insulators,  57 
International  Association  of  Steam 

Users,  221 

Congress  of  1900, 
testing  materials, 
249 


276 


INDEX 


Institute  of  Civil  Engineers,  211 

Marine  Engineers,  201 
Iron,  forging  of,  39,  113, 138 
welding  of,  1,  32,  192 

J. 

JOINING  metals, 

by  forging,  39,  113,  138 

by  fusion  (welding),  1,  32,  192 

Jottrand  and  Lulli,  229 

K. 

KNOWLEDGE       and       Scientific 

News,  22 
Knudsen,  Hans,  7 
Krupp, 189 


LABORATOIRE     du     Conservatoire 
National  des  Arts  et  Metiers  a 
Paris,  63 
Lamb     and     Wilson,     Cambridge 

University,  57 
Lap- welding,  113,  169 
Lavoisier,  23,  33 
Lead  burning,  82 
Leak  tester,  44 
Leeds  and  Butterfield,  49 
Leeds  Corporation  Tramways,  tests, 

72 

Steel  Works,  tests,  76 
Legislation,  259 
Levy,  Kene,  7 

Lewes,  Vivian  B.,  Professor,  199 
Liege,  Congress  of,  229 
Life  of  steel  pipes  and   cast-iron 

pipes,  182,  184 
Lime,  14 

sludge  in  acetylene  generators, 

quantity  produced,  14 
volume  of,  formed  by  decom- 
position, 14 

weight  of,  from  carbide,  14 
Liude,  Carl,  Professor,  7,  32 


Liquefaction,  5 
of  acetylene,  9 

atmospheric  air,  6 
Blau  gas,  19 
hydrogen,  22 
nitrogen,  7,  23,  32 
oxygen,  7,  23,  32 
Liquid  air,  source  of  oxygen,  7 
Liquid  Air  Power  and  Automobile 
Company      of      Great     Britain, 
Limited,  32 
Liquid  state,  5 
Lloyd's,  82,  175,  221 
Low  pressure 

automatic    acetylene    welding 

plant,  51 
blowpipes,  148 

non-automatic  acetylene  weld- 
ing plant,  52 
L'Oxhydrique  Fran9aise,  142 

Internationale,  139, 

229 
Lulli  and  Jottrand  blowpipe,  229 

M. 

MAGNOLITJM,  66 

Manchester     Corporation      Tram- 
ways, 77 

Steam  Users'  Asso- 
ciation, 248 
Mai-ine  boiler,  192,  198 

autogenous  welding,  200,  220 
electric  welding,  205,  212 
general  repairs,  198 
Marine      Engineer      and      Naval 

Architect,  201 
Mariotte's  law,  24 
Mauricheau-Baupr6,  22 
Mechanics'  Magazine,  191 
Melbourne,  water  mains,  182 
Metals,  cutting  of,  229 
Metric  and  English  measures,  266 
Metropolitan  Eailway,  Paris,  233 
Michaelis,  L.,  Dr.,  240 


INDEX 


277 


Microphotographic  tests,  63 
Microscopical    examination     of 

welded  metals,  4 
Minister     for      Works,      Western 

Australia,  182 
Mix,  Conrad,  7 

Moisture  in  carbide  of  calcium,  8 
Mond  gas,  184 

N. 

NATTERER,  6 
Neutral  flame,  4 
New  South  Wales,  183 

Zealand,  184 
Nitrogen,  6 

Non-automatic     acetylene      gene- 
rators, 52 

0. 

OLSZEWSKI,  elec.  welding,  89 
Oxhydrique  Franchise,  142 

Internationale,     139, 

229 

Oxidising  flame,  4 
Oxy-acetylene  blowpipe,  153 

plant     for     cutting 

metals,  229 
plant  for    welding, 

51,  58 
Oxy-coal-gas  blowpipe,  85 

plant      for      cutting 

metals,  85 

plant  for  welding,  84 
Oxy-hydrogen  blowpipe,  148,  229 
plant     for     cutting 

metals,  229,  232 
plant    for    welding, 

141 
Oxygen,  23 

Bausirigault's  process,  25 
boiling  point,  23 
Erin's  process,  25 
British      Oxygen      Company, 
Limited,  25,  32 


Oxygen — continued. 
cost  of  plant,  33 

production,  32 
critical  temperature,  23 
electrolysis  of  water,  25,  30 
evaporation,  24 
liquid,  23 

liquid  air  process,  7,  32 
pressure  for  liquefaction,  23 
cutting     metals, 

232 

solidification  of,  24 
vacuum  vessels  for,  24 

P. 

PARIS   Metropolitan   Eailway,   70, 

233 

Perkins,  Jacob,  6 
Permanent  gases,  6 
Perth,  Public  Works  Department, 

182 
Petroleum  Acts  applied  to  calcium 

carbide,  259 
Phlogiston,  23 
Phoenix  Works,  tests,  73 
Physical  states,  5 
Pictet,  Eioul,  7,  22,  23 
Pipes,  97,  110,  168,  171,  179 

cast-iron,  welding  of,  97,  110, 

124,  168 
corrosion  of  wrought-iron,  soft 

steel  and  nickel  steel,  188 
life  of  cast-iron  pipes,  184 
riveted  pipes,  180 
steel  pipes  v.  cast-iron, 

182 

wrought-iron,  178 
reports,  182 

steel,  welding  of,  124,  179 
strength  of  cast-iron,  steel  and 
riveted    pipes, 
171,  179 

riveted  v.  welded 
pipes,  171,  175, 
195 


278 


INDEX 


Poles,  electric,  welding  of,  175 
Polymerisation  of  acetylene,  16 
Polytechnicum  Zurich,  65 
Prefect  of  Police,  Paris,  252 
Pressure, 

critical,  6 

gauges,  41 

liquefaction  of  gases,  5 
Priestley,  Joseph,  F.R.S.,  23 
Proving  cylinders,  45 
Public  Works  Department, 

Perth,  182 

Sydney,  183 

Victoria,  185 

Western  Australia,  182 
Puratylene,  50 
Purifying  materials,  49 

E. 
EADLEY,  P.  E.,  266 

Eails,  cutting  of,  233 
welding  of,  69 
Range  of  explosion, 
acetylene,  10,  21 
Blau  gas,  21 
coal-gas,  21 
hydrogen,  22 
water-gas,  22 

Easch,  Dr.  H.,  Hamburg,  254 
Eeceptacle  for  carbide  of  calcium,  8 
compressed  gases,  45 
liquefied  air,  45 
Eeducing  flame,  4 
Eegnault,  Henri  Victor,  F.E.S.,  6 
Regulators,  41 

Eelative  advantage  of  acetylene  and 
hydrogen    welding, 
142 
of  acetylene  welding 

and  riveting,  225 
of    hydrogen    v.   coal 

gas,  84 

corrosion  of  wrought-iron , 
soft  steel  and  nickel  steel, 
188 


Eelative  strength  of  cast-iron,  steel 
and  riveted  pipes,  171, 
175 

strength  of  riveted  and 
welded  seams,  171,  175, 
195 

Relegation,  36 

Renard,  electrolysis  of  water,  26 
Repairs  on  marine  boilers,  82,  192, 

198,  243 
steam  boilers,  192,  195, 

243 
Reports  upon  acetylene  welding,  14, 

225,  243 
aluminium,  63 
Alumino-Thermit,  72 
electric,  201 
hydrogen,  233 
iron  and  steel  pipes, 

180 

mains  for  water,  180 
Revue  des  Eclairages,  258 
Riveted  mains,  192,  195 
pipes,  171 
seams,  192 
tanks,  224 
tubes,  171 
Riveting  v.  welding,  171,  175,  192, 

196,  225 
Royal  Society  of  Arts  Committee, 

10 
Ruck-Keene,  Henry,  201 


8 


SCHEELE,  Carl  Wilhelm,  23 
Schmidt,  Dr.,  26 
Schoop,  Dr.  M.  1).,  61 
Schuckert,  26,  149 
Scott,  Walter,  Ltd.,  Leeds,  76 
Seams,  welded,  192,  195 
Siemens,  Sir  William,  7 
Slavianoff,  electr.  weld.,  89 
Sludge-lime,  14 


INDEX 


279 


Societ^    L'Oxhydrique    Fran£aise, 

142 
Internationale, 

139,  149 
de  1'Acetylene-Dissous  de 

Sud-Est,  247 
Society  of  Arts,  Royal,  Committee, 

10 

Soldering,  82 
Solid  state,  5 

Solidification  of  oxygen,  24 
South.  Australia,  183 
Space     occupied     by     carbide      of 

calcium,  15 

Speed  of  cutting  metals,  234 
welding  metals,  157 
Steam  boilers,  192 
repairs,  195 
welding,  192 

Steam    Users'    Associations,     192, 
221 

Bavarian,  244 
Belgium,  248 
British,  221 
French,  247 
German,  221 
International,  248 
Lloyds,  221 
Manchester,  248 
Veritas,  247 

Stands  for  cylinders,  45 
Steel  pipes,  124,  179 

corrosion  of  wrought-iron,  soft 

steel  and  nickel  steel,  188 
reports,  182 

strength  of  cast-iron,  steel  and 
riveted  pipes, 

180,  184 

riveted    v.   welded 
pipes,    171,    175, 
195 

welding,  179 

Stewarts  and  Lloyds,  Ltd.,  124,  129 
Strength    of    welded    mains,    180, 
184 


Strength  of  welded  pipes,  180,  184 

seams,  180,  184 

tubes,  180,  184 

welding     v.     riveting, 

171,  175,  195 

Stretch  testing  apparatus,  46 
Stromeyer,  C.  E.,  Manchester  Steam 

Users'  Association,  248 
Suckert,  9 
Swiss  Federal  Testing  Institute,  65 

T. 

TANKS,  192,  224 

relative   cost  of  welding  and 

riveting,  195,  225 
riveting,  224 
welding,  224 
Temperature, 

of  acetylene  flame,  151,  164 

generation,  12,  16 
coal-gas  flame,  20 
critical,  6 
electric  arc,  90 
fusion  of  metals,  39,  266 
hydrogen  flame,  151 
liquefaction  of  gases,  5 
liquid  acetylene,  9 
air,  6 

hydrogen,  22 
nitrogen,  7,  23,  32 
Tension  of  liquefied  gas,  5 
Testing  Materials  Congress,  248 
Tests  of  welds : 
acetylene,  142 
aluminium,  63 
Alumino-Thermit,  72 
electric,  215 
hydrogen,  142 
main  pipes,  179 
microphotographic,  63 
microscopical,  4 
water-gas,  172 
Testing  of  cylinders,  45 
Thermal  unit,  264 
Thilorier,  5 


280 


INDEX 


Thomson,  Elihu,  91 
Tramway  rails,  welding  of,  69 
Tubes,  97,  110,  168, 179 
cast-iron,  168,  179 
life  of  steel  pipes  v.  cast-iron, 

182 

patent  welded,  168 
relative  corrosion  of  wrought- 
iron,  soft  steel,  and 
nickel  steel,  188 
strength  of   cast-iron, 
steel,    and    riveted, 
180,  184 

strength  of  cast-iron  v. 

Ferguson  pipes,  179 

strength     of     riveted 

tubes    v.   Ferguson 

pipes,  180 

strength  of  welding  v. 
riveting,  171,  175, 
195 

strength  of  wrought- 
iron  v.  cast-iron 
tubes,  184 

riveted,  171,  175,  180 
seamless,  168 
steel,  179 
welded,  148,  171 

U. 

ULLMANN,  50 

Union  des  Proprietaries  d'Appareil 
a  Acetylene,  258 

y. 

VACUUM  vessel  for  liquid  air,  24 

Vapour,  5 

Veritas,  247 

Villard,  9 

Volume, 

critical,  6 

of  gas  evolved  from  carbide  of 
calcium,  14,  54 


Volume— continued. 

lime  formed  by  decomposi- 
tion of  acetylene,  15,  19 


w. 

WATER,  electrolysis  of,  25 
Water-gas,  33,  147,  168,  252 

general,  33,  147 

welding,  147,  168 
Water  mains,  168,  171,  179 

cast-iron,  92,  110,  124,  168 

corrosion,  192,  198 

steel,  124,  179 

strength,  171,  175 

tests,  171,  179 
Wedge-welding,  169 
Weld,  3 

limit  of,  3 

perfect,  conditions  of,  3,  242 
Welding,  1 

acetylene  process,  40 

alloys,  110 

aluminium  process,  61 

Alumino-Thermic  process,  69 

autogenous,  3 

axle  gear,  78 

bar,  3 

bends,  97,  111 

Blau  gas  process,  82 

bolts,  square  and  hexagon,  118 

bootsdavits,  172 

bosses  for  drain  pipes,  131 

brass,  82 

buckles,  97,  102 

cast  iron,  97,  110,  124,  168 

chains,  97,  111 

chemical  process,  86 

clock-making,  98,  106 

coal-gas  process,  87 

coke  fire,  170 

compressed  gases,  39 

copper,  87 

crank  shafts,  118 


INDEX 


281 


Welding — contin  ued. 

cutlery,  hollow-handled  table, 

116,  123 
cycles,  98,  109 
defective,  fatal  results,  254 
description,  35 
different  systems,  39 
door  hinges,  97,  104 
drain  pockets,  129 
electric  process,  88 
end-to-end,  97,  169 
flanges,  124 
forging,  39 
forming  joints  in  thin  material, 

115 

frames,  111 
fusion,  39 
harness  rings,  105 
heterogeneous,  39 
hinge  bands,  97,  104 
hooks,  97,  104 
hoops,  97,  105,  109,  111 
hydrogen  process,  21, 139,  197 
iron,   cast,   97,  110,  122,  124, 

129 

forged,  39,  113,  138 
furniture,  98 
sheet,  97,  168 
lamp  posts,  175 
lap,  113,  169 
lead  process,  82 
mains,  electric,  gas,  water,  178 
masts,  175 
methods,  39 

pipes  and  tubes,  97,  110,  179 
point,  98,  107 
pulley  and  spokes  to  rim,  98, 

108 

window  sashes,  115 
rails,  69 
receivers,  132 
rims,  97 
rings,  97,  105 


Welding — continued. 

ship  masts,  175 

simultaneous,     of     pins     and 
pieces  to  discs,  97 

spiral  of  iron  tubing,  122 

steam  boilers,  177,  192 

gauges  to  pipes,  131 

systems,  39 

tanks,  192,  224 

thermometers  to  pipes,  131 

tubes,  97,  110,  124,  168,  179 

water-gas,  147,  168 

wedge,  169 

Werdermann,  elec.  welding,  90 

wire  and  wire  nettings,  97,  111, 
117,  120 

zinc,  82 
Western    Australia,    Minister    for 

Works,  182 
Willson,  9 
Wilson,  7 
Wiss-Draeger,  149 
Wohler,  9 

Wolff,  Paul,  Dr.,  253 
!  Wolfram  aluminium,  66 
Wrightson,  Sir  Thomas,  36 
Wroblewski,  6,  23 


ZEITSCHKIFT  fur, 

Bayerischen  Kevisions-Verein, 

240,  254 
Calcium      Carbid-Fabrikation 

und  Klein  Beleuchtung,  253, 

258 

Comprimirte  Gase,  253 
Dingler's       Polytechnisches 

Journal,  221,  236 
Gewerbeblatt     aus    Wiirtem- 

berg,  248 

Vulcan,  149 

Zerener,  Dr.,  90 


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